Rapid spectral variability of a giant flare from a magnetar in NGC 253.

Magnetars are neutron stars with extremely strong magnetic fields (1013 to 1015 gauss)1,2, which episodically emit X-ray bursts approximately 100 milliseconds long and with energies of 1040 to 1041 erg. Occasionally, they also produce extremely bright and energetic giant flares, which begin with a short (roughly 0.2 seconds), intense flash, followed by fainter, longer-lasting emission that is modulated by the spin period of the magnetar3,4 (typically 2 to 12 seconds). Over the past 40 years, only three such flares have been observed in our local group of galaxies3-6, and in all cases the extreme intensity of the flares caused the detectors to saturate. It has been proposed that extragalactic giant flares are probably a subset7-11 of short γ-ray bursts, given that the sensitivity of current instrumentation prevents us from detecting the pulsating tail, whereas the initial bright flash is readily observable out to distances of around 10 to 20 million parsecs. Here we report X-ray and γ-ray observations of the γ-ray burst GRB 200415A, which has a rapid onset, very fast time variability, flat spectra and substantial sub-millisecond spectral evolution. These attributes match well with those expected for a giant flare from an extragalactic magnetar12, given that GRB 200415A is directionally associated13 with the galaxy NGC 253 (roughly 3.5 million parsecs away). The detection of three-megaelectronvolt photons provides evidence for the relativistic motion of the emitting plasma. Radiation from such rapidly moving gas around a rotating magnetar may have generated the rapid spectral evolution that we observe.

Observation of inverse Compton emission from a long γ-ray burst.

Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission1,2. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands1-6. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock7-9. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C10,11. Here we report multi-frequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 × 10-6 to 1012 electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs.

The first pulse of the extremely bright GRB 130427A: a test lab for synchrotron shocks.

Gamma-ray burst (GRB) 130427A is one of the most energetic GRBs ever observed. The initial pulse up to 2.5 seconds is possibly the brightest well-isolated pulse observed to date. A fine time resolution spectral analysis shows power-law decays of the peak energy from the onset of the pulse, consistent with models of internal synchrotron shock pulses. However, a strongly correlated power-law behavior is observed between the luminosity and the spectral peak energy that is inconsistent with curvature effects arising in the relativistic outflow. It is difficult for any of the existing models to account for all of the observed spectral and temporal behaviors simultaneously.

A limit on the variation of the speed of light arising from quantum gravity effects.

A cornerstone of Einstein's special relativity is Lorentz invariance-the postulate that all observers measure exactly the same speed of light in vacuum, independent of photon-energy. While special relativity assumes that there is no fundamental length-scale associated with such invariance, there is a fundamental scale (the Planck scale, l(Planck) approximately 1.62 x 10(-33) cm or E(Planck) = M(Planck)c(2) approximately 1.22 x 10(19) GeV), at which quantum effects are expected to strongly affect the nature of space-time. There is great interest in the (not yet validated) idea that Lorentz invariance might break near the Planck scale. A key test of such violation of Lorentz invariance is a possible variation of photon speed with energy. Even a tiny variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing sharp features in gamma-ray burst (GRB) light-curves. Here we report the detection of emission up to approximately 31 GeV from the distant and short GRB 090510. We find no evidence for the violation of Lorentz invariance, and place a lower limit of 1.2E(Planck) on the scale of a linear energy dependence (or an inverse wavelength dependence), subject to reasonable assumptions about the emission (equivalently we have an upper limit of l(Planck)/1.2 on the length scale of the effect). Our results disfavour quantum-gravity theories in which the quantum nature of space-time on a very small scale linearly alters the speed of light.

Fermi observations of high-energy gamma-ray emission from GRB 080916C.

Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gammaray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass.

Fertility decline and gender bias in northern India.

Although it is widely acknowledged that the preference for sons is a barrier to a decline in fertility, considerable disagreement exists as to what actually happens to this preference when fertility declines in a region of low female autonomy. By analyzing the data from the National Family Health Survey (NFHS), we present evidence from northern India to show that the preference for sons is reduced when the ideal family size becomes small, even though it does not completely disappear. This finding appears to contradict trends in the juvenile sex ratio and the incidence of female feticide that suggest the intensification of gender bias. We argue that the anomaly is the result of a diffusion of prenatal sex-diagnostic techniques in regions where there is a large unmet demand for such methods. Using the NFHS data, we estimate that in northern India, girls currently constitute about 60% of the unwanted births and that the elimination of unwanted fertility has the potential to raise the sex ratio at birth to 130 boys per 100 girls.

Maternal mortality in India: an update.

This study presents estimates of maternal mortality for India from two indirect procedures, the sisterhood method and a regression method involving sex differentials in adult mortality, and compares them with estimates available from other sources. The sisterhood method is applied to the data collected in a human development survey that covered all rural areas of India in 1994, while the latter method is applied to the data on mortality and fertility rates from India's Sample Registration System. The level of maternal mortality for the early 1980s implied by the sisterhood method is found to be about 15 percent lower than the estimate for the same period derived from the method that uses the data on sex differentials in adult mortality. The estimate for the 1990s from the latter method is consistent, however, with the direct estimates available from the National Family Health Survey and the Sample Registration System. The study also discusses the socioeconomic differentials in maternal mortality implied by the sisterhood data, and spatial and temporal variations in maternal mortality derived from the regression method.

Beryllium: an easily scavenged metal ion in the environment.

This study was specifically aimed to determine the levels of beryllium in environmental samples near the vicinity of the beryllium metal plant (BMP). Air particulate samples collected at the BMP site, in the non-monsoon and monsoon seasons, showed an average beryllium concentration of 0.3 and 0.1 ng m(-3) respectively, where as rain water samples showed the beryllium values in the range of 0.01-0.2 ng ml(-1). The suspended particulate matter (dust load) at the site studied was 570 and 250 microg m(-3) in the non-monsoon and monsoon seasons respectively. The results obtained show that, in the environment, 80% of the total beryllium present is removed by rain.

Completeness of India's sample registration system: an assessment using the general growth balance method.

In the preceding issue of this journal, a generalized version of the Brass growth balance method was proposed that made it applicable to populations that are not stable and are open to migration. In this companion paper, the results of applying this new procedure to data from India's Sample Registration system for the decades 1971-80 and 1981-90 are discussed. The results at the national level show that, during the decade 1981-90, 5 percent of the deaths among men, 12 percent of the deaths among women, and about 7 percent of births were being missed by the system. Further, it is estimated that the level of under-enumeration in the 1991 Census was more than that of the 1981 Census by 0.7 percent for males and 1.4 percent for females. The paper also presents results for major Indian states.

Immobilisation of beryllium in solid waste (red-mud) by fixation and vitrification.

The objective of this study was to obtain information on the immobilization of beryllium (Be) in solid waste generated in the extraction process of beryllium from its ore, Beryl. This solid waste, termed red-mud, contains oxides of iron, aluminium, calcium, magnesium and beryllium. The red-mud waste contains beryllium at levels above the permissible limit, which prevents its disposal as solid waste. The total beryllium content in the red-mud analysed showed value ranging from 0.39 to 0.59% Be The studies showed that 50% of the total beryllium in red-mud can be extracted by water by repeated leaching over a period of 45 days. The cement mix, casting into cement blocks, was subjected to leachability studies over a period of 105 days and immobilization factor (IF factor) was determined. These IF values, of the order of 102, were compared with those obtained by performing leachability study on vitrified red-mud masses produced at different temperature conditions. Direct heating of the red-mud gave the gray coloured, non-transparent vitreous mass (as 'bad glass') showed effective immobilisation factor for beryllium in red-mud of the order of 10(4).

General growth balance method: A reformulation for populations open to migration.

This paper proposes a reformulation of the general growth balance method for estimating census and registration completeness so as to make it applicable even to populations that are affected by migration. It also discusses a new procedure of line fitting that could be useful in countries where the input data are severely affected by age misreporting. The method is applicable to countries where data on age distribution of the population are available for two points in time from either censuses or surveys. Following closely the original proposal of Brass, it involves adjusting the 'partial' birth rates for age-specific disturbances from growth and migration rates. Beyond correcting the death rates, the method is useful in inferring the relative completeness of the censuses, and in deriving a robust estimate of birth rate under certain conditions. The application of the method is illustrated using the example of the male population of the Indian state of Uttar Pradesh for the period 1981 to 1991.

Factors influencing continuation of IUD use in south India: evidence from a multivariate analysis.

This paper studies the correlates of IUD continuation, particularly in relation to quality of service provided in Karnataka, South India, by using a discrete-time logit model. Provision of follow-up services had a moderate influence on continuation, and medical check-up at insertion influenced the experience of side effects. But these effects were trivial in comparison with the overriding influence of motivational variables and of reported side effects. The IUD is retained for a limited duration in rural India where it is used mainly as a spacing device by lowly motivated young women who discontinue the method at the slightest feeling of discomfort or abnormality. If the IUD were recommended to older women for limiting childbearing by emphasizing its reversibility, it would enhance the method's popularity and improve the levels of contraceptive use among younger women.

PIP: In northern Karnataka, South India, the IUD is the most popular reversible contraceptive method but has a low continuation rate. The determinants of this pattern, with special emphasis on the role of programmatic factors, were investigated through an analysis of data from several small-scale follow-up studies of family planning acceptors conducted by the Population Research Center. A total of 713 IUD acceptors (461 rural and 252 urban) were interviewed in these studies. The mean age of IUD acceptors was 25 years; they averaged 2.3 children. 75% of rural and 58% of urban respondents had selected the IUD for spacing reasons. 45% reported IUD-related side effects such as irregular bleeding. Only 35% of respondents had their original IUD in situ at the time of follow-up and 57% had requested removal, primarily because of side effects. A multinomial logit model identified the level of motivation to use the method and the experience of real or perceived side effects as the most significant determinants of IUD continuation; unexpectedly, the quality of services provided before and after insertion was not as influential. Medical check-ups at insertion moderately reduced the experience of side effects. Women who selected the IUD for child spacing had significantly higher discontinuation rates at 3 months and were more likely to complain about side effects than those who chose the method for other reasons. A policy shift toward recommending the IUD to older, high-parity women for limiting purposes should be considered. Such a strategy might encourage contraceptive use among women who do not want more children but are concerned about child mortality and thus reluctant to undergo sterilization.

Maternal mortality in India: estimates from a regression model.

This report outlines a new technique for the estimation of maternal mortality by relating the sex differentials in mortality for people of reproductive age to the age schedule of fertility. The application of this method to the data from the Sample Registration System for 1982-86 indicates a level of maternal mortality of 580 deaths per 100,000 live births for India as a whole, 638 deaths in rural areas, and 389 deaths in urban areas. Estimates derived for the major states suggest relatively high maternal mortality in the eastern and northern parts of the country. They also indicate a substantial decline in maternal mortality since the 1960s. The decline in the birth rate is estimated to have accounted for nearly one-fourth of the decrease in the maternal death rate and 5 percent of the fall in the maternal mortality ratio in the 10-year period between 1972-76 and 1982-86. The method of estimation described here is well-suited to the data circumstances in India.

PIP: This report uses a new method for estimation of the level of maternal mortality using the relationship between sex differences in mortality among reproductive age groups and age-specific fertility. This parametric method assumes a standard age pattern of maternal mortality among women 15-49 years old. Data requirements are identified as age-specific death rates from all causes by sex, age-specific fertility rates, the ratio of maternal mortality at different ages to ages 20-24 years (country specific or a similar country's data), and the age pattern of sex ratios of death rates excluding maternal mortality. This new method is applied to data obtained from the Sample Registration System and the National Sample Surveys of India. Data obtained from Matlab, Bangladesh, are used to express the ratio of the age pattern of maternal mortality to women 20-24 years old. Age-specific fertility and mortality rates are averaged during 1982-86 for 15 major states, excluding Kerala, Punjab, Orissa, and Rajasthan states. Regressions are constructed for estimating the level of rural maternal mortality for women 20-24 years old. When the model uses the dependent variable, the sex ratio of mortality, maternal mortality at age 20-24 years is estimated at 465 deaths per 100,000 live births. When the model is fitted to female death rates, maternal mortality at age 20-24 years is 480 deaths per 100,000 live births. Further adjustments are made to conform to state patterns. Final estimation of maternal mortality under two specifications reveals a maternal mortality ratio of 568 or 591 deaths per 100,000 live births during 1982-86. An average maternal mortality ratio of 580 for India is given as the equivalent of a maternal mortality rate of 82 per 100,000 women 15-49 years old, or 21% of deaths of females 15-49 years old. State variations range widely from 20 deaths per 100,000 women in Kerala to 160 in Uttar Pradesh. This estimation is comparable to adjustment of Survey of Cause of Death estimation, suggesting the reliability of this method.

The principles and practice of rinderpest eradication.

Rinderpest can be controlled by interrupting its transmission. This objective can be achieved by implementing zoo sanitary controls to eliminate or reduce the excretion of virus or by the use of vaccine to prevent the infection of fresh hosts. For success in the eradication of rinderpest these two techniques must be combined and used within time-bound campaign frameworks. The tools required for implementing rinderpest eradication are legal powers to declare farms to be infected premises and their surroundings to be infected areas, along with a cheap and efficacious vaccine. Finally, before embarking on rinderpest eradication an epidemiologically valid strategy must be adopted, financed and placed under competent management.

Single-step bulk purification of synthetic tetrapeptide tuftsin by high performance liquid chromatography.

A protocol on reversed phase high performance liquid chromatogrpahy (RP-HPLC) using water-acetonitrile gradients under lesser stringent conditions, has been devised to obtain highly purified tuftsin in bulk amount. The protocol was also tested for two different preparations of tuftsin to yield identical quality of peptide.

Conformation of a T-cell stimulating peptide of interleukin-1 beta protein: circular dichroism studies.

A T-cell stimulating peptide Val-Gln-Gly-Glu-Glu-Ser-Asn-Asp-Lys-OH, the 163-171 fragment epitope of interleukin-1 beta (IL-1 beta), has been synthesized in solution phase and purified by reverse-phase high-performance liquid chromatography (RP-HPLC). The backbone conformation of the synthetic fragment, investigated in aqueous solution by circular dichroism (CD) spectroscopy, is qualitatively a mixture of beta-turns and random coil. Quantification of the CD spectra revealed the presence of a 9% beta-turn fraction in water at pH 7.0, suggesting the occurrence of the conformation for the epitope fragment in aqueous solution necessary for T-cell stimulation and antigenicity. Concomitant changes in CD spectra were observed with increases in the trifluoroethanol (TFE) concentration in water, and the beta-turn fraction in peptide increased to 28% at a concentration of 90% TFE. This helicogenic solvent, as well as other solvents such as methanol, acetonitrile and dioxane (all favouring an ordered structure in peptides), failed to induce any alpha-helical conformation in the IL-1 beta (163-171) fragment, and CD spectra were attributed to only beta-turn ordered structure. This beta-turn structure has also been found to be a theoretically preferred conformation using Chou-Fasman proclivity data and is in accordance with the presence of an all-beta-globular conformation for its parent molecule IL-1 beta. Thus, the beta-turn conformation is probably involved in retention of T-cell stimulation activity in this synthetic epitope.

Discovery of intense gamma-ray flashes of atmospheric origin.

Detectors aboard the Compton Gamma Ray Observatory have observed an unexplained terrestrial phenomenon: brief, intense flashes of gamma rays. These flashes must originate in the atmosphere at altitudes above at least 30 kilometers in order to escape atmospheric absorption and reach the orbiting detectors. At least a dozen such events have been detected over the past 2 years. The photon spectra from the events are very hard (peaking in the high-energy portion of the spectrum) and are consistent with bremsstrahlung emission from energetic (million-electron volt) electrons. The most likely origin of these high-energy electrons, although speculative at this time, is a rare type of high-altitude electrical discharge above thunderstorm regions.

Priority areas in demographic research.

"This paper reviews...demographic development [in India] since the mid-1970s and highlights important data gaps in respect to (i) fertility and family planning (ii) mortality and morbidity along with priority areas for exploratory research. The paper notes that during the past two decades, [the] demographic data-base in India has improved considerably. Fertility levels have begun to fall in many places and mortality has continued its rapid downward course...."

Identification and size variation of terminal fragments of sheep pox virus genome.

Terminal fragments of sheep pox virus DNA identified by snap-back analysis showed terminal covalent cross-links. Southern blot hybridization using a terminal fragment probe confirmed the termini and terminal repeats (common sequences) of the sheep pox virus genome. Terminal fragment length variability was observed between virus isolates.