The complex circumstellar environment of supernova 2023ixf

The early evolution of a supernova (SN) can reveal information about the environment and the progenitor star. When a star explodes in vacuum, the first photons to escape from its surface appear as a brief, hours-long shock-breakout flare1,2, followed by a cooling phase of emission. However, for stars exploding within a distribution of dense, optically thick circumstellar material (CSM), the first photons escape from the material beyond the stellar edge and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating3. Early serendipitous observations2,4 that lacked ultraviolet (UV) data were unable to determine whether the early emission is heating or cooling and hence the nature of the early explosion event. Here we report UV spectra of the nearby SN 2023ixf in the galaxy Messier 101 (M101). Using the UV data as well as a comprehensive set of further multiwavelength observations, we temporally resolve the emergence of the explosion shock from a thick medium heated by the SN emission. We derive a reliable bolometric light curve that indicates that the shock breaks out from a dense layer with a radius substantially larger than typical supergiants.

A rotating white dwarf shows different compositions on its opposite faces

White dwarfs, the extremely dense remnants left behind by most stars after their death, are characterized by a mass comparable to that of the Sun compressed into the size of an Earth-like planet. In the resulting strong gravity, heavy elements sink towards the centre and the upper layer of the atmosphere contains only the lightest element present, usually hydrogen or helium^1,2. Several mechanisms compete with gravitational settling to change a white dwarf's surface composition as it cools³, and the fraction of white dwarfs with helium atmospheres is known to increase by a factor of about 2.5 below a temperature of about 30,000 kelvin^4-8; therefore, some white dwarfs that appear to have hydrogen-dominated atmospheres above 30,000 kelvin are bound to transition to be helium-dominated as they cool below it. Here we report observations of ZTF J203349.8+322901.1, a transitioning white dwarf with two faces: one side of its atmosphere is dominated by hydrogen and the other one by helium. This peculiar nature is probably caused by the presence of a small magnetic field, which creates an inhomogeneity in temperature, pressure or mixing strength over the surface^9-11. ZTF J203349.8+322901.1 might be the most extreme member of a class of magnetic, transitioning white dwarfs-together with GD 323 (ref. ¹²), a white dwarf that shows similar but much more subtle variations. This class of white dwarfs could help shed light on the physical mechanisms behind the spectral evolution of white dwarfs.

An infrared transient from a star engulfing a planet

Planets with short orbital periods (roughly under 10 days) are common around stars like the Sun^1,2. Stars expand as they evolve and thus we expect their close planetary companions to be engulfed, possibly powering luminous mass ejections from the host star^3-5. However, this phase has never been directly observed. Here we report observations of ZTF SLRN-2020, a short-lived optical outburst in the Galactic disk accompanied by bright and long-lived infrared emission. The resulting light curve and spectra share striking similarities with those of red novae^6,7-a class of eruptions now confirmed⁸ to arise from mergers of binary stars. Its exceptionally low optical luminosity (approximately 10³⁵ erg s^-1) and radiated energy (approximately 6.5 × 10⁴¹ erg) point to the engulfment of a planet of fewer than roughly ten Jupiter masses by its Sun-like host star. We estimate the Galactic rate of such subluminous red novae to be roughly between 0.1 and several per year. Future Galactic plane surveys should routinely identify these, showing the demographics of planetary engulfment and the ultimate fate of planets in the inner Solar System.

A dense 0.1-solar-mass star in a 51-minute-orbital-period eclipsing binary

Of more than a thousand known cataclysmic variables (CVs), where a white dwarf is accreting from a hydrogen-rich star, only a dozen have orbital periods below 75 minutes^1-9. One way to achieve these short periods requires the donor star to have undergone substantial nuclear evolution before interacting with the white dwarf^10-14, and it is expected that these objects will transition to helium accretion. These transitional CVs have been proposed as progenitors of helium CVs^13-18. However, no known transitional CV is expected to reach an orbital period short enough to account for most of the helium CV population, leaving the role of this evolutionary pathway unclear. Here we report observations of ZTF J1813+4251, a 51-minute-orbital-period, fully eclipsing binary system consisting of a star with a temperature comparable to that of the Sun but a density 100 times greater owing to its helium-rich composition, accreting onto a white dwarf. Phase-resolved spectra, multi-band light curves and the broadband spectral energy distribution allow us to obtain precise and robust constraints on the masses, radii and temperatures of both components. Evolutionary modelling shows that ZTF J1813+4251 is destined to become a helium CV binary, reaching an orbital period under 20 minutes, rendering ZTF J1813+4251 a previously missing link between helium CV binaries and hydrogen-rich CVs.

A 62-minute orbital period black widow binary in a wide hierarchical triple

Over a dozen millisecond pulsars are ablating low-mass companions in close binary systems. In the original 'black widow', the eight-hour orbital period eclipsing pulsar PSR J1959+2048 (PSR B1957+20)¹, high-energy emission originating from the pulsar² is irradiating and may eventually destroy³ a low-mass companion. These systems are not only physical laboratories that reveal the interesting results of exposing a close companion star to the relativistic energy output of a pulsar, but are also believed to harbour some of the most massive neutron stars⁴, allowing for robust tests of the neutron star equation of state. Here we report observations of ZTF J1406+1222, a wide hierarchical triple hosting a 62-minute orbital period black widow candidate, the optical flux of which varies by a factor of more than ten. ZTF J1406+1222 pushes the boundaries of evolutionary models⁵, falling below the 80-minute minimum orbital period of hydrogen-rich systems. The wide tertiary companion is a rare low-metallicity cool subdwarf star, and the system has a Galactic halo orbit consistent with passing near the Galactic Centre, making it a probe of formation channels, neutron star kick physics⁶ and binary evolution.

A WC/WO star exploding within an expanding carbon-oxygen-neon nebula

The final fate of massive stars, and the nature of the compact remnants they leave behind (black holes and neutron stars), are open questions in astrophysics. Many massive stars are stripped of their outer hydrogen envelopes as they evolve. Such Wolf-Rayet stars¹ emit strong and rapidly expanding winds with speeds greater than 1,000 kilometres per second. A fraction of this population is also helium-depleted, with spectra dominated by highly ionized emission lines of carbon and oxygen (types WC/WO). Evidence indicates that the most commonly observed supernova explosions that lack hydrogen and helium (types Ib/Ic) cannot result from massive WC/WO stars^2,3, leading some to suggest that most such stars collapse directly into black holes without a visible supernova explosion⁴. Here we report observations of SN 2019hgp, beginning about a day after the explosion. Its short rise time and rapid decline place it among an emerging population of rapidly evolving transients^5-8. Spectroscopy reveals a rich set of emission lines indicating that the explosion occurred within a nebula composed of carbon, oxygen and neon. Narrow absorption features show that this material is expanding at high velocities (greater than 1,500 kilometres per second), requiring a compact progenitor. Our observations are consistent with an explosion of a massive WC/WO star, and suggest that massive Wolf-Rayet stars may be the progenitors of some rapidly evolving transients.

Opportunities for neuromorphic computing algorithms and applications

Neuromorphic computing technologies will be important for the future of computing, but much of the work in neuromorphic computing has focused on hardware development. Here, we review recent results in neuromorphic computing algorithms and applications. We highlight characteristics of neuromorphic computing technologies that make them attractive for the future of computing and we discuss opportunities for future development of algorithms and applications on these systems.

A transient radio source consistent with a merger-triggered core collapse supernova

[Figure: see text].

Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g

We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus [B. McKernan, K. E. S. Ford, I. Bartos et al., Astrophys. J. Lett. 884, L50 (2019)AJLEEY2041-821310.3847/2041-8213/ab4886] and is unlikely [<O(0.01%))] due to intrinsic variability of this source. The lack of color evolution implies that it is not a supernova and instead is strongly suggestive of a constant temperature shock. Other false-positive events, such as microlensing or a tidal disruption event, are ruled out or constrained to be <O(0.1%). If the flare is associated with S190521g, we find plausible values of total mass M_{BBH}∼100  M_{⊙}, kick velocity v_{k}∼200  km s^{-1} at θ∼60° in a disk with aspect ratio H/a∼0.01 (i.e., disk height H at radius a) and gas density ρ∼10^{-10}  g cm^{-3}. The merger could have occurred at a disk migration trap (a∼700r_{g}; r_{g}≡GM_{SMBH}/c^{2}, where M_{SMBH} is the mass of the active galactic nucleus supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a reencountering with the disk in ∼1.6  yr(M_{SMBH}/10^{8}  M_{⊙})(a/10^{3}r_{g})^{3/2}.

A fast radio burst localized to a massive galaxy

Intense, millisecond-duration bursts of radio waves (named fast radio bursts) have been detected from beyond the Milky Way¹. Their dispersion measures-which are greater than would be expected if they had propagated only through the interstellar medium of the Milky Way-indicate extragalactic origins and imply contributions from the intergalactic medium and perhaps from other galaxies². Although several theories exist regarding the sources of these fast radio bursts, their intensities, durations and temporal structures suggest coherent emission from highly magnetized plasma^3,4. Two of these bursts have been observed to repeat^5,6, and one repeater (FRB 121102) has been localized to the largest star-forming region of a dwarf galaxy at a cosmological redshift of 0.19 (refs. ^7-9). However, the host galaxies and distances of the hitherto non-repeating fast radio bursts are yet to be identified. Unlike repeating sources, these events must be observed with an interferometer that has sufficient spatial resolution for arcsecond localization at the time of discovery. Here we report the localization of a fast radio burst (FRB 190523) to a few-arcsecond region containing a single massive galaxy at a redshift of 0.66. This galaxy is different from the host of FRB 121102, as it is a thousand times more massive, with a specific star-formation rate (the star-formation rate divided by the mass) a hundred times smaller.

A hot and fast ultra-stripped supernova that likely formed a compact neutron star binary

Compact neutron star binary systems are produced from binary massive stars through stellar evolution involving up to two supernova explosions. The final stages in the formation of these systems have not been directly observed. We report the discovery of iPTF 14gqr (SN 2014ft), a type Ic supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.2 solar masses) and low kinetic energy (≈2 × 10⁵⁰ ergs). Early photometry and spectroscopy reveal evidence of shock cooling of an extended helium-rich envelope, likely ejected in an intense pre-explosion mass-loss episode of the progenitor. Taken together, we interpret iPTF 14gqr as evidence for ultra-stripped supernovae that form neutron stars in compact binary systems.

SIFTING FOR SAPPHIRES: SYSTEMATIC SELECTION OF TIDAL DISRUPTION EVENTS IN iPTF

We present results from a systematic selection of tidal disruption events (TDEs) in a wide-area (4800 deg²), g + R band, Intermediate Palomar Transient Factory (iPTF) experiment. Our selection targets typical optically-selected TDEs: bright (>60% flux increase) and blue transients residing in the center of red galaxies. Using photometric selection criteria to down-select from a total of 493 nuclear transients to a sample of 26 sources, we then use follow-up UV imaging with the Neil Gehrels Swift Telescope, ground-based optical spectroscopy, and light curve fitting to classify them as 14 Type Ia supernovae (SNe Ia), 9 highly variable active galactic nuclei (AGNs), 2 confirmed TDEs, and 1 potential core-collapse supernova. We find it possible to filter AGNs by employing a more stringent transient color cut (g - r < -0.2 mag); further, UV imaging is the best discriminator for filtering SNe, since SNe Ia can appear as blue, optically, as TDEs in their early phases. However, when UV-optical color is unavailable, higher precision astrometry can also effectively reduce SNe contamination in the optical. Our most stringent optical photometric selection criteria yields a 4.5:1 contamination rate, allowing for a manageable number of TDE candidates for complete spectroscopic follow-up and real-time classification in the ZTF era. We measure a TDE per galaxy rate of 1.7 - 1.3 + 2.9 × 10 - 4 gal - 1 yr - 1 (90% CL in Poisson statistics). This does not account for TDEs outside our selection criteria, thus may not reflect the total TDE population, which is yet to be fully mapped.

What's in a number? Recommending practicality in the DATA 2000 patient limits

According to the Substance Abuse and Mental Health Services Administration, 2.4 million individuals have an opioid use disorder (OUD). Yet, nearly 80 percent of them-more than 1.9 million people-do not receive treatment. Medication-assisted treatment (MAT), specifically with buprenorphine, has proven to be effective in treating patients with OUDs while also reducing costs to the healthcare system, criminal justice system, and workforce. Despite its effectiveness, barriers to MAT continue to exist. Consequently, many individuals must wait months, if not years, to receive treatment. This article analyzes the US Department of Health and Human Services' final rule (Final Rule) on MAT, common barriers to treatment, and the cost-benefit of treatment in light of the current opioid abuse epidemic. The article finds that while the Final Rule was a step in the right direction, it does not go far enough to adequately address the epidemic. Finally, the article proposes practical recommendations for increasing patient access to treatment for OUDs, including increasing the patient limit for highly qualified addiction treatment providers so that they can practice addiction medicine on a full-time basis and exempting buprenorphine products labeled by the US Food and Drug Administration for direct administration from the practitioner's patient limit.

Spiking neural networks for handwritten digit recognition-Supervised learning and network optimization

We demonstrate supervised learning in Spiking Neural Networks (SNNs) for the problem of handwritten digit recognition using the spike triggered Normalized Approximate Descent (NormAD) algorithm. Our network that employs neurons operating at sparse biological spike rates below 300Hz achieves a classification accuracy of 98.17% on the MNIST test database with four times fewer parameters compared to the state-of-the-art. We present several insights from extensive numerical experiments regarding optimization of learning parameters and network configuration to improve its accuracy. We also describe a number of strategies to optimize the SNN for implementation in memory and energy constrained hardware, including approximations in computing the neuronal dynamics and reduced precision in storing the synaptic weights. Experiments reveal that even with 3-bit synaptic weights, the classification accuracy of the designed SNN does not degrade beyond 1% as compared to the floating-point baseline. Further, the proposed SNN, which is trained based on the precise spike timing information outperforms an equivalent non-spiking artificial neural network (ANN) trained using back propagation, especially at low bit precision. Thus, our study shows the potential for realizing efficient neuromorphic systems that use spike based information encoding and learning for real-world applications.

A radio counterpart to a neutron star merger

Gravitational waves have been detected from a binary neutron star merger event, GW170817. The detection of electromagnetic radiation from the same source has shown that the merger occurred in the outskirts of the galaxy NGC 4993, at a distance of 40 megaparsecs from Earth. We report the detection of a counterpart radio source that appears 16 days after the event, allowing us to diagnose the energetics and environment of the merger. The observed radio emission can be explained by either a collimated ultrarelativistic jet, viewed off-axis, or a cocoon of mildly relativistic ejecta. Within 100 days of the merger, the radio light curves will enable observers to distinguish between these models, and the angular velocity and geometry of the debris will be directly measurable by very long baseline interferometry.

iPTF16geu: A multiply imaged, gravitationally lensed type Ia supernova

We report the discovery of a multiply imaged, gravitationally lensed type Ia supernova, iPTF16geu (SN 2016geu), at redshift z = 0.409. This phenomenon was identified because the light from the stellar explosion was magnified more than 50 times by the curvature of space around matter in an intervening galaxy. We used high-spatial-resolution observations to resolve four images of the lensed supernova, approximately 0.3 arc seconds from the center of the foreground galaxy. The observations probe a physical scale of ~1 kiloparsec, smaller than is typical in other studies of extragalactic gravitational lensing. The large magnification and symmetric image configuration imply close alignment between the lines of sight to the supernova and to the lens. The relative magnifications of the four images provide evidence for substructures in the lensing galaxy.

Incidental non-inguinals hernias in totally extra-peritoneal hernia repair

INTRODUCTION

Totally extra-peritoneal (TEP) inguinal hernia repair allows identification and repair of incidental non-inguinal groin hernias. We assessed the prevalence of incidental hernias during TEP inguinal hernia repair and identified the risk factors for incidental hernias.

MATERIALS AND METHODS

Consecutive patients undergoing TEP repair from May 2005 to November 2012 were the study cohort. Inspection for ipsilateral femoral, obturator and rarer varieties of hernia was undertaken during TEP repair. Patient characteristics and operative findings were recorded on a prospectively collected database.

RESULTS

A total of 1,532 TEP repairs were undertaken in 1,196 patients. Ninety-three patients were excluded due to incomplete data, leaving 1,103 patients and 1,404 hernias for analyses (1,380 male; 802 unilateral and 301 bilateral repairs; median age, 59 years). Among the 37 incidental hernias identified (2.6% of cases), the most common type of incidental hernia was femoral (n=32, 2.3%) followed by obturator (n=2, 0.1%). Increasing age was associated with an increased risk of incidental hernia, with a significant linear trend (p<0.01). The risk for patients >60 years of age was 4.0% vs 1.4% for those aged <60 years (p<0.01). Incidental hernias were found in 29.2% of females vs 2.2% of males, (p<0.0001). Risk of incidental hernia in those with a recurrent inguinal hernia was 3.0% vs 2.6% for primary repair (p=0.79).

CONCLUSIONS

Incidental hernias during TEP inguinal hernia repair were found in 2.6% of cases and, though infrequent, could cause complications if left untreated. The risk of incidental hernia increased with age and was significantly higher in patients aged >60 years and in females.

Effect of foam sclerotherapy on healing and long-term recurrence in chronic venous leg ulcers

INTRODUCTION

The ESCHAR trial showed that superficial venous surgery and compression in chronic venous ulceration achieved a 24-week healing rate of 65% and 12-month recurrence rate of 12%. Foam sclerotherapy treatment is an alternative to surgery. The aim of this study is to assess the effect of foam sclerotherapy on ulcer healing and recurrence in chronic venous leg ulcers.

METHODS

Chronic venous leg ulcers (CEAP [clinical, aetiological, anatomical and pathological elements] 5 and CEAP 6) with superficial venous reflux were treated between March 2006 and June 2011 with ultrasound-guided foam sclerotherapy and compression.Venous duplex was performed on all legs before and after treatment. Twenty-four-week ulcer healing and one- and four-year ulcer recurrence rates were calculated using Kaplan–Meier survival analysis.

RESULTS

Two hundred legs (186 patients) with chronic venous ulcers (CEAP 5: n ¼ 163 and CEAP 6: n ¼ 37) were treated with foam sclerotherapy. Complete occlusion was achieved in 185/200 (92.5%) limbs, short segment occlusion in 14/200 (7%) limbs and one leg segment failed to occlude. One patient suffered an asymptomatic non-occlusive deep vein thrombosis (DVT) diagnosed on duplex scan at one week and one presented with an occlusive DVT three weeks following a normal scan at one week. One patient developed an asymptomatic occlusive DVT at two weeks following a non-occlusive DVT diagnosed on initial one-week scan. Eighteen patients were lost to follow-up (3 moved away and 15 died of unrelated causes). The 24-week healing rate was 71.1% and one- and four-year recurrence rates were 4.7% and 28.1%, respectively.

CONCLUSION

Foam sclerotherapy is effective in abolition of superficial venous reflux and may contribute to similar ulcer healing and long-term recurrence rates to superficial venous surgery. Foam sclerotherapy is an attractive alternative to surgery in this group of patients.

Abdominal cocoon: an unusual presentation of small bowel obstruction

Abdominal cocoon is a rare condition. It presents as a thick whitish membrane which covers bowel loops. Because of this presentation, it is also called as sclerosing encapsulating peritonitis. It is usually diagnosed intra operatively. Treatment of this condition involves resection of the membrane and release of adhesions. Pre-operatively, patient is investigated for recurrent episodes of small bowel obstructions. However, preoperative diagnosis does not change the treatment and management. Investigations done preoperatively help in expediting the treatment with planned laparotomy.

Abstract P2-02-10: Evaluation of apparent diffusion coefficient to predict grade, micro-invasion and invasion in DCIS

PURPOSE: To evaluate the role of apparent diffusion coefficient (ADC) values in distinguishing DCIS grades and identifying the presence of micro-invasive/invasive disease.

METHODS AND MATERIALS:

REB approved study with informed consent obtained from 70 women (age 36-84) scheduled for core-biopsy with results of 71 non-invasive/high-risk breast lesions. All patients underwent surgery and were assessed pre-operatively using diffusion weighted (DWI)-MRI. Lesion size, morphology and ADC values were recorded. The Kruskal Wallis or one-way ANOVA test and Pearson correlation coefficient were used to study the association between ADC values and the analyzed MRI lesion characteristics. Logistic regression analysis was used to evaluate the ability of ADC values to predict the presence of invasion.

RESULTS:

Of 71 cases, 45.1% were imaged on a 3T magnet and 54.9% on 1.5 T. Final pathology demonstrated invasive cancer in 26.8%, micro-invasion in 18.3% and pure DCIS in 59.2%. On 3T, mean ADC value was 1.20 ×10-3 mm2/s ± 0.48 (SD) (range, 0.47 - 1.78 ×10-3 mm2/s) for non-high grade DCIS, 1.23 × 10-3 mm2/s ± 0.40 (SD) (range, 0.26 - 1.77 ×10-3 mm2/s) for high-grade DCIS, and 1.15 × 10-3 mm2/s ± 0.45 (SD) (range, 0.26 - 1.75 ×10-3 mm2/s) for invasive/microinvasive disease. On 1.5T, mean ADC value was 1.04 × 10-3 mm2/s ± 0.41 (SD) (range, 0.15 - 1.85 ×10-3 mm2/s) for non-high grade DCIS, 1.01 × 10-3 mm2/s ± 0.37 (SD) (range, 0.06 - 1.76 ×10-3 mm2/s) for high-grade DCIS, and 1.11 × 10-3 mm2/s ± 0.30 (SD) (range, 0.64 - 1.76 ×10-3 mm2/s) for invasive/microinvasive disease. Based on logistic regression analysis, mean ADC value was not a significant predictor for invasiveness using 1.5 T [OR = 2.6 (95% CI (0.409, 17.12)), p = 0.3] or 3T [OR = 0.4 (95% CI (0.076, 2.399)), p = 0.3]

CONCLUSION: Mean ADC acquired using a 1.5T or 3T MRI was unable to predict high-grade or invasive disease in biopsy-proven DCIS lesions. Further work is exploring voxel-based approaches that may better appreciate tumor heterogeneity and identify sub-regions of tumor with these higher risk features.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-02-10.

An outburst from a massive star 40 days before a supernova explosion

Some observations suggest that very massive stars experience extreme mass-loss episodes shortly before they explode as supernovae, as do several models. Establishing a causal connection between these mass-loss episodes and the final explosion would provide a novel way to study pre-supernova massive-star evolution. Here we report observations of a mass-loss event detected 40 days before the explosion of the type IIn supernova SN 2010mc (also known as PTF 10tel). Our photometric and spectroscopic data suggest that this event is a result of an energetic outburst, radiating at least 6 × 10(47) erg of energy and releasing about 10(-2) solar masses of material at typical velocities of 2,000 km s(-1). The temporal proximity of the mass-loss outburst and the supernova explosion implies a causal connection between them. Moreover, we find that the outburst luminosity and velocity are consistent with the predictions of the wave-driven pulsation model, and disfavour alternative suggestions.

Analysis of 32 common susceptibility genetic variants and their combined effect in predicting risk of Type 2 diabetes and related traits in Indians

AIMS

Recent genome-wide association studies have identified several Type 2 diabetes-related loci. We investigated the effect of susceptibility genetic variants, individually, together and in combination with conventional risk factors, on Type 2 diabetes and diabetes-related traits in Indians.

METHODS

We genotyped 33 variants in 1808 Indian patients and 1549 control subjects and performed association analyses with Type 2 diabetes and related traits using an additive model for individual variant and for genetic risk score based on 32 polymorphisms. The discriminatory value of genetic risk over conventional risk factors was analysed using receiver-operating characteristics curve analysis.

RESULTS

The allelic odds ratio ranged from 1.01 (95% CI 0.85-1.19) to 1.66 (95% CI 1.32-2.01) for single-variant analyses. Although, only 16 variants had significant odds ratios, the direction of association for others was similar to earlier reports. The odds ratio for Type 2 diabetes at each genetic risk score point was 1.11 (95% CI 1.09-1.14; P = 5.6 × 10(-17)) and individuals with extremes of genetic risk score (≥ 29.0 and ≤ 17.0) had a 7.5-fold difference in risk of Type 2 diabetes. The discrimination rate between control subjects and patients improved marginally on addition of genetic risk score to conventional risk factors (area under curve = 0.959 and 0.963, respectively; P = 0.001). Of all the quantitative traits analysed, MC4R variants showed strong association with BMI (P = 4.1 × 10(-4)), fat mass per cent (P = 2.4 × 10(-4)) and other obesity-related traits, including waist circumference and hip circumference (P = 2.0 × 10(-3) for both), as well as insulin resistance (P =0.02).

CONCLUSIONS

We replicated the association of well-established common variants with Type 2 diabetes in Indians and observed a similar association as reported in Western populations. Combined analysis of 32 variants aids identification of subgroups at increased risk of Type 2 diabetes, but adds only a minor advantage over conventional risk factors.

Evaluation of Composition and Antimicrobial Activity of Supercritical Fluid Extract of Leaves of Vitex negundo

Supercritical fluid extract of leaves of Vitex negundo was tested for its antimicrobial potential and was compared with that of ethanol extract, ether extract and hydrodistilled oil of leaves. The chemical constituents of extracts were studied by chromatographic techniques. Extracts were evaluated for antimicrobial potential against bacterial strains like Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and yeast Candida albicans. Extracts showed prominent antibacterial activity against Bacillus subtilis and Staphylococcus aureus. Supercritical fluid extract exhibited good antibacterial potential.

Pre-operative inspiratory muscle training preserves postoperative inspiratory muscle strength following major abdominal surgery - a randomised pilot study

INTRODUCTION

The aim of this pilot study was to assess the effect of pre-operative inspiratory muscle training (IMT) on respiratory variables in patients undergoing major abdominal surgery.

PATIENTS AND METHODS

Respiratory muscle strength (maximum inspiratory [MIP] and expiratory [MEP] mouth pressure) and pulmonary functions were measured at least 2 weeks before surgery in 80 patients awaiting major abdominal surgery. Patients were then allocated randomly to one of four groups (Group A, control; Group B, deep breathing exercises; Group C, incentive spirometry; Group D, specific IMT). Patients in groups B, C and D were asked to train twice daily, each session lasting 15 min, for at least 2 weeks up to the day before surgery. Outcome measurements were made immediately pre-operatively and postoperatively.

RESULTS

In groups A, B and C, MIP did not increase from baseline to pre-operative assessments. In group D, MIP increased from 51.5 cmH(2)O (median) pre-training to 68.5 cmH(2)O (median) post-training pre-operatively (P < 0.01). Postoperatively, groups A, B and C showed a fall in MIP from baseline (P < 0.01, P < 0.01) and P = 0.06, respectively). No such significant reduction in postoperative MIP was seen in group D (P = 0.36).

CONCLUSIONS

Pre-operative specific IMT improves MIP pre-operatively and preserves it postoperatively. Further studies are required to establish if this is associated with reduced pulmonary complications.

The importance of early carotid endarterectomy in symptomatic patients

INTRODUCTION

Early carotid endarterectomy (CEA) in symptomatic patients may prevent repeat cerebral events. This study investigates the relationship between waiting time for CEA and the incidence of repeat cerebral events prior to surgery in symptomatic patients.

PATIENTS AND METHODS

A prospective database of consecutive patients undergoing CEA between January 2002 and December 2006 was reviewed. Repeat event rates prior to surgery were calculated using Kaplan-Meier analysis and predictive factors identified using Cox regression analysis.

RESULTS

A total of 118 patients underwent CEA for non-disabling stroke, TIA and amaurosis fugax. Repeat cerebral events occurred in 34 of 118 (29%) patients at a median 51 days (range, 2-360 days) after the first event. The estimated risk of repeat events was 2% at 7 days and 9% at 1 month after first event (Kaplan-Meier survival analysis). Age (HR 1.059; 95% CI 1.014-1.106; P = 0.009] was identified as a predictor of repeat events. Patients underwent surgery at median 97 days (range, 7-621 days) after the first event. Eleven of 60 (18%) patients waiting < or = 97 days for surgery and 23 of 58 (40%) patients waiting > 97 days had repeat events. (P = 0.011, chi-squared test).

CONCLUSIONS

Delays in surgery should be reduced in order to minimise repeat cerebral events in patients with symptomatic carotid stenosis, particularly in the elderly population.

FTO gene variants are strongly associated with type 2 diabetes in South Asian Indians

AIMS AND HYPOTHESIS

Variants of the FTO (fat mass and obesity associated) gene are associated with obesity and type 2 diabetes in white Europeans, but these associations are not consistent in Asians. A recent study in Asian Indian Sikhs showed an association with type 2 diabetes that did not seem to be mediated through BMI. We studied the association of FTO variants with type 2 diabetes and measures of obesity in South Asian Indians in Pune.

METHODS

We genotyped, by sequencing, two single nucleotide polymorphisms, rs9939609 and rs7191344, in the FTO gene in 1,453 type 2 diabetes patients and 1,361 controls from Pune, Western India and a further 961 population-based individuals from Mysore, South India.

RESULTS

We observed a strong association of the minor allele A at rs9939609 with type 2 diabetes (OR per allele 1.26; 95% CI 1.13-1.40; p = 3 x 10(-5)). The variant was also associated with BMI but this association appeared to be weaker (0.06 SDs; 95% CI 0.01-0.10) than the previously reported effect in Europeans (0.10 SDs; 95% CI 0.09-0.12; heterogeneity p = 0.06). Unlike in the Europeans, the association with type 2 diabetes remained significant after adjusting for BMI (OR per allele for type 2 diabetes 1.21; 95% CI 1.06-1.37; p = 4.0 x 10(-3)), and also for waist circumference and other anthropometric variables.

CONCLUSIONS

Our study replicates the strong association of FTO variants with type 2 diabetes and similar to the study in North Indians Sikhs, shows that this association may not be entirely mediated through BMI. This could imply underlying differences between Indians and Europeans in the mechanisms linking body size with type 2 diabetes.

Diagnosis of metastatic carcinoid in mesenteric lymph node by fine needle aspiration cytology

Although carcinoid tumor is a relatively common neoplasm in surgical pathology, fine needle aspiration cytology (FNAC) as a method of primary diagnosis has only been reported a few times. We report the case of a 55-year-old male patient who presented with colicky pain in the abdomen and a vague mass in the right lumbar region. Ultrasonographic study showed an enlarged mesenteric lymph node. Ultrasonography-guided FNAC revealed cellular smears with neuroendocrine cellular arrangement and morphology. The cytomorphologic characteristics of carcinoid tumors are distinctive enough for diagnosis. A diagnosis of metastatic carcinoid was given. 5-hydroxyindolacetic acid in 24-hour urine turned out to be high. Histopathology and immunohistochemistry studies also confirmed the diagnosis. Thus, FNAC can be a useful and safe tool in the diagnosis of carcinoid tumors.

Significance of limb trauma as an initiating factor in chronic leg ulceration

OBJECTIVES

To assess differences in clinical outcomes between patients with traumatic and spontaneous leg ulcers.

METHODS

Consecutive leg ulcer follow-up patients seen between April 2004 and October 2005 in a specialist leg ulcer clinic were asked about the mechanism of the original ulceration. Twenty-four-week healing and 12-month recurrence rates were calculated using Kaplan-Meier analysis and outcomes were compared between groups with traumatic and spontaneous ulcers.

RESULTS

Of the 300 patients assessed, 38 were excluded (incomplete data). In the remaining 262 patients, cause of ulceration was traumatic in 116/262 (44%) and spontaneous in 146/262 (56%). Age, ankle brachial pressure index <0.85 and venous reflux were equally distributed between groups with traumatic and spontaneous ulcers (P = 0.470, 0.793, 0.965 respectively, Chi-square test). Twenty-four-week healing rates were 81% for traumatic and 67% for spontaneous ulcers (P = 0.015, Log-Rank test). Twelve-month recurrence rates were 32% for traumatic and 33% for spontaneous ulcers (P = 0.970, Log-rank test). Patients with traumatic ulcers suffered a total of 53 ulcer recurrences (median 0, range 0-4) compared with 89 in patients with spontaneous ulcers (median 0, range 0-8) (P < 0.001, Mann-Whitney U test).

CONCLUSION

Approximately half of all leg ulcer patients recall a traumatic event. When managed in leg ulcer clinic, traumatic ulcers heal faster and recur less frequently than spontaneous ulcers.

Residual Venous Reflux after Superficial Venous Surgery Does Not Predict Ulcer Recurrence

OBJECTIVE

The aim of this study was to investigate the importance of venous reflux in ulcer recurrence following saphenous surgery.

METHODS

Ulcerated legs (CEAP 5 and 6) with saphenous reflux were treated with superficial venous surgery plus compression as part of a clinical trial. Patients unfit for general anaesthesia (GA) underwent limited surgery under local anaesthesia (LA). Reflux in superficial and deep segments and venous refill times (VRTs) were assessed before surgery and 3-12 months post-operatively using duplex and digital photoplethysmography respectively.

RESULTS

Of 185 patients treated with surgery, 15 failed to heal and 26 did not have a follow-up duplex. Within 3 years, 25 of the remaining 144 patients (17%) developed ulcer recurrence. Using a Cox regression model, the presence of residual venous reflux and change in reflux pattern were not found to be risk factors for ulcer recurrence (p=ns). LA was used in 4/25 patients who recurred compared to 28/119 who did not (p=0.60; Chi-square test). For legs with recurrence, median VRT before surgery was 10.5s (range 5-29) compared to 11s (range 6-36) after surgery (p=0.097, Wilcoxon Signed Rank test). However, in legs without recurrence, median VRT increased from 10s (range 3-48) to 15s (range 4-48) after surgery (p<0.001).

CONCLUSION

Residual reflux following saphenous surgery is not the most important predictor of venous ulcer recurrence. Poor venous function as demonstrated by VRT may be a better predictor of recurrence in these patients.

An unusually brilliant transient in the galaxy M85

Historically, variable and transient sources have both surprised astronomers and provided new views of the heavens. Here we report the discovery of an optical transient in the outskirts of the lenticular galaxy Messier 85 in the Virgo cluster. With a peak absolute R magnitude of -12, this event is distinctly brighter than novae, but fainter than type Ia supernovae (which are expected in a population of old stars in lenticular galaxies). Archival images of the field do not show a luminous star at that position with an upper limit in the g filter of about -4.1 mag, so it is unlikely to be a giant eruption from a luminous blue variable star. Over a two-month period, the transient source emitted radiation energy of almost 10(47) erg and subsequently faded in the optical sky. It is similar to, but six times more luminous at peak than, an enigmatic transient in the galaxy M31 (ref. 1). A possible origin of M85 OT2006-1 is a stellar merger. If so, searches for similar events in nearby galaxies will not only allow study of the physics of hyper-Eddington sources, but also probe an important phase in the evolution of stellar binary systems.

Primary malignant melanoma of left buccal mucosa with metastasis in thyroid: a case report

Primary oral malignant melanomas are rare with an incidence of .2 to 8% of all melanomas. Less than 1% of them arise on buccal mucosa. Grossly they arise as a black macule with irregular borders & are commonly of mucosal lentiginous type. They appear at a higher stage and are aggressive with a 5 yr survival rate of 10-25%. 39% of metastasis in thyroid occur from skin (melanomas) and melanomas produce a thyroid mass while the original source remains occult. We report a case of oral malignant melanoma of left buccal mucosa for its rarity and its spread to cervical lymph nodes and thyroid.

The Ulcerated Leg Severity Assessment score for prediction of venous leg ulcer healing

BACKGROUND

The aim of the study was to create a reliable scoring system for the prediction of venous ulcer healing in patients treated with compression.

METHODS

A prospective baseline study to identify risk factors for venous ulcer healing was undertaken between March 1999 and August 2001. All patients were treated with multilayer compression. A number of variables were related to 24-week healing rates. A Cox regression model was used to identify risk factors that predicted ulcer healing, from which a scoring system was developed and validated prospectively between February 2004 and March 2005.

RESULTS

In the baseline study of 229 patients, patient age, ulcer chronicity and venous refill time (VRT) of 20 s or less were identified as risk factors. Using these factors and hazard ratios from the Cox regression analysis, the following formula was devised: Ulcerated Leg Severity Assessment (ULSA) score=age+chronicity-50 (when VRT is greater than 20 s). Patients with an ULSA score of 50 or less had higher 24-week ulcer healing rates than those with higher scores in both the baseline study (P<0.001, log rank test) and the validation study performed in 86 patients (P=0.007, log rank test).

CONCLUSION

The ULSA score may help to identify patients with venous ulcers unlikely to respond to conventional treatment who could be offered alternative therapy.

Common variants in the TCF7L2 gene are strongly associated with type 2 diabetes mellitus in the Indian population

AIMS AND HYPOTHESIS

India has the greatest number of diabetic subjects in any one country, but the genetic basis of type 2 diabetes mellitus in India is poorly understood. Common non-coding variants in the transcription factor 7-like 2 gene (TCF7L2) have recently been strongly associated with increased risk of type 2 diabetes in European populations. We investigated whether TCF7L2 variants are also associated with type 2 diabetes mellitus in the Indian population.

MATERIALS AND METHODS

We genotyped type 2 diabetes patients (n = 955) and ethnically matched control subjects (n = 399) by sequencing three single nucleotide polymorphisms (SNPs) (rs7903146, rs12255372 and rs4506565) in TCF7L2.

RESULTS

We observed a strong association with all the polymorphisms, including rs12255372 (odds ratio [OR] 1.50 [95% CI = 1.24-1.82], p = 4.0 x 10(-5)), rs4506565 (OR 1.48 [95% CI = 1.24-1.77], p = 2.0 x 10(-5)) and rs7903146 (OR 1.46 [95% CI = 1.22-1.75], p = 3.0 x 10(-5)). All three variants showed increased relative risk when homozygous rather than heterozygous, with the strongest risk for rs12255372 (OR 2.28 [95% CI = 1.40-3.72] vs OR 1.43 [95% CI = 1.11-1.83]). We found no association of the TCF7L2 genotypes with age at diagnosis, BMI or WHR, but the risk genotype at rs12255372 was associated with higher fasting plasma glucose (p = 0.001), higher 2-h plasma glucose (p = 0.0002) and higher homeostasis model assessment of insulin resistance (HOMA-R; p = 0.012) in non-diabetic subjects.

CONCLUSIONS

Our study in Indian subjects replicates the strong association of TCF7L2 variants with type 2 diabetes in other populations. It also provides evidence that variations in TCF7L2 may play a crucial role in the pathogenesis of type 2 diabetes by influencing both insulin secretion and insulin resistance. TCF7L2 is an important gene for determining susceptibility to type 2 diabetes mellitus and it transgresses the boundaries of ethnicity.

A novel explosive process is required for the γ-ray burst GRB 060614

Over the past decade, our physical understanding of gamma-ray bursts (GRBs) has progressed rapidly, thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (> 2 s) GRBs are associated with the explosive deaths of massive stars ('collapsars', ref. 1), which produce accompanying supernovae; the short-duration (< or = 2 s) GRBs have a different origin, which has been argued to be the merger of two compact objects. Here we report optical observations of GRB 060614 (duration approximately 100 s, ref. 10) that rule out the presence of an associated supernova. This would seem to require a new explosive process: either a massive collapsar that powers a GRB without any associated supernova, or a new type of 'engine', as long-lived as the collapsar but without a massive star. We also show that the properties of the host galaxy (redshift z = 0.125) distinguish it from other long-duration GRB hosts and suggest that an entirely new type of GRB progenitor may be required.

Relativistic ejecta from X-ray flash XRF 060218 and the rate of cosmic explosions

Over the past decade, long-duration gamma-ray bursts (GRBs)--including the subclass of X-ray flashes (XRFs)--have been revealed to be a rare variety of type Ibc supernova. Although all these events result from the death of massive stars, the electromagnetic luminosities of GRBs and XRFs exceed those of ordinary type Ibc supernovae by many orders of magnitude. The essential physical process that causes a dying star to produce a GRB or XRF, and not just a supernova, is still unknown. Here we report radio and X-ray observations of XRF 060218 (associated with supernova SN 2006aj), the second-nearest GRB identified until now. We show that this event is a hundred times less energetic but ten times more common than cosmological GRBs. Moreover, it is distinguished from ordinary type Ibc supernovae by the presence of 10(48) erg coupled to mildly relativistic ejecta, along with a central engine (an accretion-fed, rapidly rotating compact source) that produces X-rays for weeks after the explosion. This suggests that the production of relativistic ejecta is the key physical distinction between GRBs or XRFs and ordinary supernovae, while the nature of the central engine (black hole or magnetar) may distinguish typical bursts from low-luminosity, spherical events like XRF 060218.

A photometric redshift of z = 6.39 ± 0.12 for GRB 050904

Gamma-ray bursts (GRBs) and their afterglows are the most brilliant transient events in the Universe. Both the bursts themselves and their afterglows have been predicted to be visible out to redshifts of z approximately 20, and therefore to be powerful probes of the early Universe. The burst GRB 000131, at z = 4.50, was hitherto the most distant such event identified. Here we report the discovery of the bright near-infrared afterglow of GRB 050904 (ref. 4). From our measurements of the near-infrared afterglow, and our failure to detect the optical afterglow, we determine the photometric redshift of the burst to be z = 6.39 - 0.12 + 0.11 (refs 5-7). Subsequently, it was measured spectroscopically to be z = 6.29 +/- 0.01, in agreement with our photometric estimate. These results demonstrate that GRBs can be used to trace the star formation, metallicity, and reionization histories of the early Universe.

The afterglow and elliptical host galaxy of the short gamma-ray burst GRB 050724

Despite a rich phenomenology, gamma-ray bursts (GRBs) are divided into two classes based on their duration and spectral hardness--the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing their origin to star-forming galaxies, and hence the death of massive stars, and indicating an energy release of about 10(51) erg. While theoretical arguments suggest that short GRBs are produced in the coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10-1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors.

The afterglow of GRB 050709 and the nature of the short-hard gamma-ray bursts

The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class of bursts, which are suspected on theoretical grounds to result from the coalescence of neutron-star or black-hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst, GRB 050709, whose accurate position allows us to associate it unambiguously with a star-forming galaxy at redshift z = 0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates.

Characteristics of gestational diabetic mothers and their babies in an Indian diabetes clinic

AIMS AND OBJECTIVES

To compare clinical and metabolic features of mothers with gestational diabetes (GDM) and their offspring with those in non-diabetic pregnancies at the King Edward Memorial Hospital, Pune, India.

MATERIALS AND METHODS

Antenatal information was obtained from hospital records. GDM was diagnosed by 75 g OGTT (Oral Glucose Tolerance Test) in clinically high-risk women. Anthropometric measurements of mother and the babies were recorded within 24h of delivery and a maternal blood sample collected for hematological and biochemical measurements.

RESULTS

Between the period Jan 1998 to December 2003,265 women with gestational diabetes were treated in our Unit. Forty nine percent had first-degree relatives with diabetes. Compared to non-diabetic mothers (n=215) GDM mothers were older (29.0 vs. 26.0y, p<0.001), more obese (body mass index- BMI 26.0 vs. 22.0 kg/m2, p<0.001), centrally obese (Waist hip ratio-WHR 0.89 vs 0.86, p<0.001), adipose (sum of 4 skinfolds 98.4 vs. 61.4 mm, p<0.001) and had higher blood pressure (127/80 vs. 122/70 mmHg, p<0.001). GDM mothers had higher concentrations of plasma triglycerides (195.0 vs. 153.0 mg/dl, p<0.01); blood hemoglobin (11.7 vs 10.9 g/dl, p<0.001) and higher platelet count but lower concentration of HDL cholesterol and albumin. Sixty percent GDM mothers and 34% of non-diabetic mothers were delivered by caesarean-section, 23% of GDM mothers delivered pre term (<37 wk). Despite the smaller gestation, babies of GDM mothers were heavier (BW 2950.0 vs. 2824.0g, p<0.001, adjusted for gender), longer (48.9 vs. 48.0 cm, p<0.01) and more adipose (sum of 2 skinfolds 10.5 vs. 8.5 mm). Only 5% of babies born to GDM mothers weighed > 4000 g but 30% were >90th centile of birth weight of babies born to non-diabetic mothers. Babies of GDM mothers suffered higher neonatal morbidity.

CONCLUSIONS

GDM mothers in urban India are more obese and more adipose than non-diabetic mothers, frequently have a family history of diabetes and show metabolic features of insulin resistance syndrome, suggesting high cardiovascular risk. Neonates of GDM mothers are heavier, longer and more adipose than those born to non-diabetic mothers, and suffer higher neonatal morbidity.

Detection of a radio counterpart to the 27 December 2004 giant flare from SGR 1806–20

It was established over a decade ago that the remarkable high-energy transients known as soft gamma-ray repeaters (SGRs) are located in our Galaxy and originate from neutron stars with intense (< or = 10(15)G) magnetic fields-so-called 'magnetars'. On 27 December 2004, a giant flare with a fluence exceeding 0.3 erg cm(-2) was detected from SGR 1806-20. Here we report the detection of a fading radio counterpart to this event. We began a monitoring programme from 0.2 to 250 GHz and obtained a high-resolution 21-cm radio spectrum that traces the intervening interstellar neutral hydrogen clouds. Analysis of the spectrum yields the first direct distance measurement of SGR 1806-20: the source is located at a distance greater than 6.4 kpc and we argue that it is nearer than 9.8 kpc. If correct, our distance estimate lowers the total energy of the explosion and relaxes the demands on theoretical models. The energetics and the rapid decay of the radio source are not compatible with the afterglow model that is usually invoked for gamma-ray bursts. Instead, we suggest that the rapidly decaying radio emission arises from the debris ejected during the explosion.

The sub-energetic γ-ray burst GRB 031203 as a cosmic analogue to the nearby GRB 980425

Over the six years since the discovery of the gamma-ray burst GRB 980425, which was associated with the nearby (distance approximately 40 Mpc) supernova 1998bw, astronomers have debated fiercely the nature of this event. Relative to bursts located at cosmological distance (redshift z approximately 1), GRB 980425 was under-luminous in gamma-rays by three orders of magnitude. Radio calorimetry showed that the explosion was sub-energetic by a factor of 10. Here we report observations of the radio and X-ray afterglow of the recent GRB 031203 (refs 5-7), which has a redshift of z = 0.105. We demonstrate that it too is sub-energetic which, when taken together with the low gamma-ray luminosity, suggests that GRB 031203 is the first cosmic analogue to GRB 980425. We find no evidence that this event was a highly collimated explosion viewed off-axis. Like GRB 980425, GRB 031203 appears to be an intrinsically sub-energetic gamma-ray burst. Such sub-energetic events have faint afterglows. We expect intensive follow-up of faint bursts with smooth gamma-ray light curves (common to both GRB 031203 and 980425) to reveal a large population of such events.

A distance of 133–137 parsecs to the Pleiades star cluster

Nearby 'open' clusters of stars (those that are not gravitationally bound) have played a crucial role in the development of stellar astronomy because, as a consequence of the stars having a common age, they provide excellent natural laboratories to test theoretical stellar models. Clusters also play a fundamental part in determining distance scales. The satellite Hipparcos surprisingly found that an extensively studied open cluster--the Pleiades (also known as the Seven Sisters)--had a distance of D = 118 +/- 4 pc (refs 2, 3), about ten per cent smaller than the accepted value. The discrepancy generated a spirited debate because the implication was that either current stellar models were incorrect by a surprising amount or Hipparcos was giving incorrect distances. Here we report the orbital parameters of the bright double star Atlas in the Pleiades, using long-baseline optical/infrared interferometry. From the data we derive a firm lower bound of D > 127 pc, with the most likely range being 133 < D < 137 pc. Our result reaffirms the fidelity of current stellar models.

A common origin for cosmic explosions inferred from calorimetry of GRB030329

Past studies have suggested that long-duration gamma-ray bursts have a 'standard' energy of E(gamma) approximately 10(51) erg in the ultra-relativistic ejecta, after correcting for asymmetries in the explosion ('jets'). But a group of sub-energetic bursts, including the peculiar GRB980425 associated with the supernova SN1998bw (E(gamma) approximately 10(48) erg), has recently been identified. Here we report radio observations of GRB030329 that allow us to undertake calorimetry of the explosion. Our data require a two-component explosion: a narrow (5 degrees opening angle) ultra-relativistic component responsible for the gamma-rays and early afterglow, and a wide, mildly relativistic component that produces the radio and optical afterglow more than 1.5 days after the explosion. The total energy release, which is dominated by the wide component, is similar to that of other gamma-ray bursts, but the contribution of the gamma-rays is energetically minor. Given the firm link of GRB030329 with SN2003dh, our result indicates a common origin for cosmic explosions in which, for reasons not yet understood, the energy in the highest-velocity ejecta is extremely variable.