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.

MRI­based neoadjuvant therapy indication in middle and low rectal cancer.

OBJECTIVE: The aim of this study was to evaluate the indication of neoadjuvant therapy in patients with middle and low rectal cancer based on MRI examination. BACKGROUND: In spite of noticeable advances in the diagnosis of rectal cancer, the optimal treatment remains highly debated. Current guidelines advise the use of neoadjuvant therapy in UICC stage II patients or higher. However, in clinical praxis, there is gradual implementation of new criterions and variables used in rectal cancer stage evaluation, the fact of which influences the treatment choice. The most important emerging variables taken currently into account are the distance from mesorectal fascia, circumferential resection margin, extramural venous invasion and intersphincteric plane, all of which can be evaluated using the MRI examination. METHODS: The accuracy of MRI staging was compared with definite histopathological results from resected tumors. Patient data were prospectively collected between the years 2013 and 2018 at 3rd Surgical Clinic, Faculty of Medicine, Comenius University in Bratislava, Slovakia. Data from 101 patients were gathered and divided into two groups, according to the localization of tumor within rectum, while 9 patients were excluded from the study because of benign lesion diagnosis based upon final histopathologic evaluation. RESULTS: In 92 evaluated patients, no significant change was noted between MRI and histopathological T-staging. However, in N-staging, significant differences were noted between preoperative MRI staging and postoperative histopathological staging. CONCLUSION: The results of this study demonstrate inefficient preoperative lymph node staging, suggesting overtreatment of rectal cancer patients. Although the use of neoadjuvant therapy has led to great advances in modern cancer treatment, it is connected with a number of side effects and therefore should be indicated only for patients who can benefit from this treatment (Tab. 1, Fig. 3, Ref. 16).

Anthropogenic control over wintertime oxidation of atmospheric pollutants.

During winter in the mid-latitudes, photochemical oxidation is significantly slower than in summer and the main radical oxidants driving formation of secondary pollutants, such as fine particulate matter and ozone, remain uncertain, owing to a lack of observations in this season. Using airborne observations, we quantify the contribution of various oxidants on a regional basis during winter, enabling improved chemical descriptions of wintertime air pollution transformations. We show that 25-60% of NOx is converted to N2O5 via multiphase reactions between gas-phase nitrogen oxide reservoirs and aerosol particles, with ~93% reacting in the marine boundary layer to form >2.5 ppbv ClNO2. This results in >70% of the oxidizing capacity of polluted air during winter being controlled, not by typical photochemical reactions, but from these multiphase reactions and emissions of volatile organic compounds, such as HCHO, highlighting the control local anthropogenic emissions have on the oxidizing capacity of the polluted wintertime atmosphere.

Formaldehyde production from isoprene oxidation across NOx regimes.

The chemical link between isoprene and formaldehyde (HCHO) is a strong, non-linear function of NOx (= NO + NO2). This relationship is a linchpin for top-down isoprene emission inventory verification from orbital HCHO column observations. It is also a benchmark for overall photochemical mechanism performance with regard to VOC oxidation. Using a comprehensive suite of airborne in situ observations over the Southeast U.S., we quantify HCHO production across the urban-rural spectrum. Analysis of isoprene and its major first-generation oxidation products allows us to define both a "prompt" yield of HCHO (molecules of HCHO produced per molecule of freshly-emitted isoprene) and the background HCHO mixing ratio (from oxidation of longer-lived hydrocarbons). Over the range of observed NOx values (roughly 0.1 - 2 ppbv), the prompt yield increases by a factor of 3 (from 0.3 to 0.9 ppbv ppbv-1), while background HCHO increases by a factor of 2 (from 1.6 to 3.3 ppbv). We apply the same method to evaluate the performance of both a global chemical transport model (AM3) and a measurement-constrained 0-D steady state box model. Both models reproduce the NOx dependence of the prompt HCHO yield, illustrating that models with updated isoprene oxidation mechanisms can adequately capture the link between HCHO and recent isoprene emissions. On the other hand, both models under-estimate background HCHO mixing ratios, suggesting missing HCHO precursors, inadequate representation of later-generation isoprene degradation and/or under-estimated hydroxyl radical concentrations. Detailed process rates from the box model simulation demonstrate a 3-fold increase in HCHO production across the range of observed NOx values, driven by a 100% increase in OH and a 40% increase in branching of organic peroxy radical reactions to produce HCHO.

Instrumentation and Measurement Strategy for the NOAA SENEX Aircraft Campaign as Part of the Southeast Atmosphere Study 2013.

Natural emissions of ozone-and-aerosol-precursor gases such as isoprene and monoterpenes are high in the southeast of the US. In addition, anthropogenic emissions are significant in the Southeast US and summertime photochemistry is rapid. The NOAA-led SENEX (Southeast Nexus) aircraft campaign was one of the major components of the Southeast Atmosphere Study (SAS) and was focused on studying the interactions between biogenic and anthropogenic emissions to form secondary pollutants. During SENEX, the NOAA WP-3D aircraft conducted 20 research flights between 27 May and 10 July 2013 based out of Smyrna, TN. Here we describe the experimental approach, the science goals and early results of the NOAA SENEX campaign. The aircraft, its capabilities and standard measurements are described. The instrument payload is summarized including detection limits, accuracy, precision and time resolutions for all gas-and-aerosol phase instruments. The inter-comparisons of compounds measured with multiple instruments on the NOAA WP-3D are presented and were all within the stated uncertainties, except two of the three NO2 measurements. The SENEX flights included day- and nighttime flights in the Southeast as well as flights over areas with intense shale gas extraction (Marcellus, Fayetteville and Haynesville shale). We present one example flight on 16 June 2013, which was a daytime flight over the Atlanta region, where several crosswind transects of plumes from the city and nearby point sources, such as power plants, paper mills and landfills, were flown. The area around Atlanta has large biogenic isoprene emissions, which provided an excellent case for studying the interactions between biogenic and anthropogenic emissions. In this example flight, chemistry in and outside the Atlanta plumes was observed for several hours after emission. The analysis of this flight showcases the strategies implemented to answer some of the main SENEX science questions.

STK11/LKB1 germline mutations in the first Peutz-Jeghers syndrome patients identified in Slovakia.

Peutz-Jeghers syndrome (PJS) is characterized by number of hamartomatous polyps in the gastrointestinal tract and by mucocutaneous hypermelanocytic lesions at different sites. Older patients have an increased risk of the cancers of small intestine, stomach, pancreas, colon, esophagus, ovary, testis, uterus, breast and lung. In majority of PJS cases, the germline mutations in serine/threonine kinase STK11/LKB1 gene were found to be associated with disease. Here we report the results of a first mutational screen of STK11/LKB1 in PJS patients characterized in Slovak population. The first patient with unusual carcinoma of duodenum was a sporadic case and carried c.842delC change residing in a mutational C6 repeat hotspot. Neither the polyp nor the tumor of the patient displayed the loss of heterozygosity at the site of mutation suggesting different mechanism involved in the formation of polyp and tumor in this case. The second patient belonged to a three-generation family with typical PJS features but not cancers. Interestingly, the patient displayed concomitant occurrence of adenomatous and hamartomatous polyps. Molecular analysis revealed an IVS2+1A>G mutation that alters the second intron 5' splice site and was shown to lead to aberrant splicing mediated by the U12-dependent spliceosome. The same mutation was present in the 9 affected members of the family but in none of their normal relatives. We also observed novel c. IVS2+61G>A unclassified variant, and recurrent IVS2+24G>T and 3UTR+129C>T polymorphisms. Based on the achieved results, we could offer predictive genetic testing and counseling to other members of the patient's families.

[Trends in first marriages from 1961 to 1988]. / Evolution de la nuptialite des celibataires de 1961 a 1988.

PIP: Trends in first marriage in Czechoslovakia are analyzed for the period 1961-1988. A general decline in the popularity of marriage is noted as being in common with most other European countries, particularly for older persons. The existence of social policies that benefit only married couples, such as those regarding housing allocation, is not seen to affect significantly the trend away from marriage.^ieng

[Twenty-second conference of the Czechoslovak Demographic Society: "The Demographic Position of Czechoslovakia within Europe and the World"]. / XXII. demograficka konference CSDS "Demograficke Postaveni Ceskoslovenska v Ramci Evropy a Sveta".

PIP: This is a collection of short papers presented at a conference held in Prague, Czechoslovakia, in 1991. The focus of the conference was on the demographic changes that have occurred in Czechoslovakia since World War II and their relationship to such changes in the rest of Europe and elsewhere in the world. Essay topics include fertility trends; contraceptive prevalence, including abortion rates; living standards and health care; and changes in the age structure. Some data for selected countries are included for comparison. (SUMMARY IN ENG AND RUS)^ieng

[Reflections on recent and future population development]. / Nekolik uvah o soucasnem a budoucim populacnim vyvoji.

PIP: The author discusses current population dynamics in Czechoslovakia and forecasts the emergence of new trends following the political changes of 1989. The emergence of both cohabitation and sexual sterilization is discussed. The author predicts declines in mortality, induced abortions, fertility, and nuptiality combined with a growth in fertility outside marriage. (SUMMARY IN ENG AND RUS)^ieng

[Regional differences concerning divorce in Czechoslovakia]. / Regionalni rozdily v rozvodovosti v CSSR.

PIP: Regional differences in divorce rates in Czechoslovakia since the 1960s are considered. The authors note that such differences are declining but are still significant. The regions with the highest divorce rates remain Prague and Northern and Western Bohemia. Northern and Eastern Slovakia continue to have the lowest rates. (SUMMARY IN ENG AND RUS)^ieng

[Regional trends in fertility in Slovakia, 1910-1980]. / Regionalni vyvoj plodnosti na Slovensku v letech 1910 az 1980.

PIP: Regional trends in fertility in Slovakia, Czechoslovakia, are analyzed for the period 1910-1980. The focus is on differences in fertility and in the timing of the transition to lower fertility by region. It is noted that although significant fertility differences occurred over the transition period, there has been a recent trend toward similar fertility levels throughout the area. (SUMMARY IN ENG AND RUS)^ieng

[Fertility evolution in Slovakia during the period 1880-1910]. / Vyvoj plodnosti na Slovensku v letech 1880-1910

PIP: Fertility trends in Slovakia during the period 1880-1910 are analyzed using the fertility indexes developed by Ansley J. Coale. The analysis shows that a general decline in marital fertility did not occur until the first decade of the twentieth century. (summary in ENG, RUS)^ieng