Low-energy M1 states in deformed nuclei: spin-scissors or spin-flip?

The low-energy $M1$ states in deformed $^{164}$Dy and spherical $^{58}$Ni are explored in the framework of fully self-consistent Quasiparticle Random-Phase Approximation (QRPA) with various Skyrme forces. The main attention is paid to orbital and spin $M1$ excitations. The obtained results are compared with the prediction of the low-energy {\it spin-scissors} $M1$ resonance suggested within Wigner Function Moments (WFM) approach. A possible relation of this resonance to low-energy spin-flip excitations is analyzed. In connection with recent WFM studies, we consider evolution of the low-energy spin-flip states in $^{164}$Dy with deformation (from the equilibrium value to the spherical limit). The effect of tensor forces is briefly discussed. It is shown that two groups of $1^+$ states observed at 2.4-4 MeV in $^{164}$Dy are rather explained by fragmentation of the orbital $M1$ strength than by the occurrence of the collective spin-scissors resonance. In general, our calculations do not confirm the existence of this resonance.Comment: 7 pages, 7 figures, submitted to Physics of Atomic Nuclei. arXiv admin note: text overlap with arXiv:2102.13580. As compared with the previous version, Ref. [1] was removed, Ref [33] was replaced, description of Fig. 3 was modifie

Molecular Structure of Pyrazinamide: A Critical Assessment of Modern Gas Electron Diffraction Data from Three Laboratories

Otlyotov AA, Girichev, Georgiy V, Rykov AN, Glodde T, Vishnevskiy Y. Molecular Structure of Pyrazinamide: A Critical Assessment of Modern Gas Electron Diffraction Data from Three Laboratories. JOURNAL OF PHYSICAL CHEMISTRY A. 2020;124(25):5204-5211.Accuracy and precision of molecular parameters determined by modern gas electron diffraction have been investigated. Diffraction patterns of gaseous pyrazinamide have been measured independently in three laboratories, in Bielefeld (Germany), Ivanovo (Russia), and Moscow (Russia). All data sets have been analyzed in equal manner using a highly controlled background elimination procedure and flexible restraints in molecular structure refinement. In detailed examination and comparison of the obtained results we have determined the average experimental precision of 0.004 angstrom for bond lengths and 0.2 degrees for angles. The corresponding average deviations of the refined parameters from the ae-CCSD(T)/cc-pwCVTZ theoretical values were 0.003 angstrom and 0.2 degrees. The average precision for refined amplitudes of interatomic vibrations was determined to be 0.005 angstrom. It is recommended to take into account these values in calculations of total errors for refined parameters of other molecules with comparable complexity

Microscopic analysis of dipole electric and magnetic strengths in 156^{156}Gd

The dipole electric ($E1$) and magnetic ($M1$) strengths in strongly deformed $^{156}$Gd are investigated within a fully self-consistent Quasiparticle Random Phase Approximation (QRPA) with Skyrme forces SV-bas, SLy6 and SG2. We inspect, on the same theoretical footing, low-lying dipole states and the isovector giant dipole resonance in $E1$ channel and orbital scissors resonance as well as spin-flip giant resonance in $M1$ channel. Besides, $E1$ toroidal mode and low-energy spin-flip $M1$ excitations are considered. The calculations show a good agreement with available experimental data, except for the recent NRF measurements of M. Tamkas et al for $M1$ strength at 4-6 MeV, where, in contradiction with our calculations and previous $(p,p')$ data, almost no $M1$ strength was observed.Comment: 8 pages, 4 figure

КОМОРБИДНОСТЬ И ПРОГНОЗИРОВАНИЕ РИСКА ВОЗНИКНОВЕНИЯ ПОСЛЕОПЕРАЦИОННЫХ ИНФЕКЦИОННЫХ ОСЛОЖНЕНИЙ У БОЛЬНЫХ ТУБЕРКУЛЕЗНЫМ СПОНДИЛИТОМ

Goal of the study: to study co-morbidity and risk of post-operative infectious complications in tuberculous spondylitis patients with concurrent non-specific spinal osteomyelitis as per ASA, PITSS scales and Charlson score.Materials and methods. Surgical treatment of 41 patients with infectious spondylitis was retrospectively analyzed. Patients were divided into 2 groups. Tuberculous spondylitis patients were included into group 1 – 24 (58.5%), and those suffering from non-specific spinal osteomyelitis were included into group 2 (17.0-41.5%) More than half of tuberculous spondylitis patients were HIV positive (13/54.3%) and 16 out of 24 patients (66.7%) had generalized form of tuberculosis. The survival forecast for the patients after surgery was estimated by Charlson score, ASA score was used for evaluation of surgical and anesthetic risks, and risk of postoperative complications was assessed by PITSS (Postoperative infection treatment score for the spine) (2012).Results. Early and late infectious complications were detected in 4 (9.7%) of patients with ASA at 3-4 scores, Charlson score exceeding 5 and high risk as per PITSS (more than 21 scores). Tuberculous spondylitis patients had Charlson score exceeding 5 and high risk as per ASA (4 scores) more often compared to those suffering from non-specific spinal osteomyelitis. The majority of infectious spondylitis patients (28/57.5%) had medium and high risk of postoperative complications development as per PITSS. HIV positive tuberculous spondylitis patients had two fold risk of postoperative complications development compared to those HIV negative (χ2 = 4.53, OR = 2.76, p = 0.0012). Цель исследования: изучение коморбидности и риска возникновения послеоперационных инфекционных осложнений у больных туберкулезным спондилитом (ТС) и неспецифическим остеомиелитом позвоночника (НОП) по шкалам ASA, PITSS и индексу коморбидности Чарлсона (ИКЧ).Материалы и методы. Проведен ретроспективный анализ хирургического лечения 41 пациента с инфекционными спондилитами (ИС). Пациенты были разбиты на 2 группы. Больные ТС вошли в 1-ю группу - 24 (58,5%), 2-ю группу (17,0-41,5%) составили пациенты с НОП. Более половины больных ТС (13/54,3%) имели ВИЧ-инфекцию, у 16/24 (66,7%) пациентов имелся генерализованный туберкулез. Прогноз выживаемости больных после проведенного оперативного лечения рассчитан по ИКЧ, дана оценка степени риска операции и наркоза по шкале ASA, проведено прогнозирование риска послеоперационных осложнений по шкале PITSS (Postoperative infection treatment score for the spine) (2012).Результаты. Ранние и поздние инфекционные осложнения выявлены у 4 (9,7%) больных с риском по ASA 3-4 cт., ИКЧ более 5 баллов и PITSS высокой степени риска (более 21 балла). У больных ТС ИКЧ более 5 баллов и высокая степень риска по ASA (4 ст.) встречались чаще, чем среди больных НОП (p ≤ 0,05). Большинство пациентов с ИС (28/57,5%) имели средний и высокий риск развития ПОО по шкале PITSS. У ВИЧ-позитивных пациентов с ТС риск их возникновения был в 2 раза выше, чем у ВИЧ-негативных пациентов (χ2 = 4,53, OR = 2,76, p = 0,0012)

Влияние эволюции лучевых методов диагностики на хирургическое представление о фазах и стадиях острого панкреатита

In modern pancreatology, diagnostics of acute pancreatitis is one of the most complex and urgent problems. In recent decades, the incidence of acute pancreatitis (AP) has more than doubled and now it exceeds 25% among acute surgical diseases. Pancreonecrosis accounts for about 20–35% of all complications. General and postoperative mortality reaches 15–45%. Modern radiology methods in patients with AP and pancreatic necrosis aid in determination of disease form and its complications. In this article, the importance of radiological methods for treatment planning is reviewed. Close attention is paid to the interpretation of computer tomography (CT) data using various CT-scales and classifications. High incidence among young and healthy people highlights socio-economic significance of AP. Therefore, in this literature review, we focus on the publications and clinical cases of acute pancreatitis. В современной панкреатологии проблема диагностики острого панкреатита – одна из наиболее сложных и актуальных. За последние десятилетия заболеваемость острым панкреатитом увеличилась более чем в 2 раза и превышает 25% в структуре острых хирургических заболеваний. Панкреонекроз составляет около 20–35% среди всех осложнений. Общая и послеоперационная летальность достигает 15–45%. Применение современных методов лучевой диагностики у больных острым панкреатитом и панкреонекрозом позволяет определить форму болезни и выявить ее осложнения. В данном обзоре литературы рассматривается значение лучевых методов диагностики в планировании лечебной тактики у больных острым панкреатитом. Пристальное внимание уделено интерпретации данных компьютерной томографии с применением различных КТ-шкал и классификаций. Высокая заболеваемость лиц молодого и трудоспособного возраста придает этой проблеме важное социально-экономическое значение. Поэтому в настоящем обзоре проанализированы данные литературы и клинические случаи острого панкреатита.

Influence of Antipodally Coupled Iodine and Carbon Atoms on the Cage Structure of 9,12-I2-closo-1,2-C2B10H10 : An Electron Diffraction and Computational Study

Because of the comparable electron scattering abilities of carbon and boron, the electron diffraction structure of the C2v-symmetric molecule closo-1,2-C2B10H12 (1), one of the building blocks of boron cluster chemistry, is not as accurate as it could be. On that basis, we have prepared the known diiodo derivative of 1, 9,12-I2-closo-1,2-C2B10H10 (2), which has the same point-group symmetry as 1 but in which the presence of iodine atoms, with their much stronger ability to scatter electrons, ensures much better structural characterization of the C2B10 icosahedral core. Furthermore, the influence on the C2B10 geometry in 2 of the antipodally positioned iodine substituents with respect to both carbon atoms has been examined using the concerted application of gas electron diffraction and quantum chemical calculations at the MP2 and density functional theory (DFT) levels. The experimental and computed molecular geometries are in good overall agreement. Molecular dynamics simulations used to obtain vibrational parameters, which are needed for analyzing the electron diffraction data, have been performed for the first time for this class of compound. According to DFT calculations at the ZORA-SO/BP86 level, the 11B chemical shifts of the boron atoms to which the iodine substituents are bonded are dominated by spin-orbit coupling. Magnetically induced currents within 2 have been calculated and compared to those for [B12H12]2-, the latter adopting a regular icosahedral structure with Ih point-group symmetry. Similar total current strengths are found but with a certain anisotropy, suggesting that spherical aromaticity is present; electron delocalization in the plane of the hetero atoms in 2 is slightly hindered compared to that for [B12H12]2-, presumably because of the departure from ideal icosahedral symmetry

Wall-to-wall mapping of carbon loss within the Chornobyl Exclusion Zone after the 2020 catastrophic wildfire

Key message We propose a framework to derive the direct loss of aboveground carbon stocks after the 2020 wildfire in forests of the Chornobyl Exclusion Zone using optical and radar Sentinel satellite data. Carbon stocks were adequately predicted using stand-wise inventory data and local combustion factors where new field observations are impossible. Both the standalone Sentinel-1 backscatter delta (before and after fire) indicator and radar-based change model reliably predicted the associated carbon loss. Context The Chornobyl Exclusion Zone (CEZ) is a mosaic forest landscape undergoing dynamic natural disturbances. Local forests are mostly planted and have low ecosystem resilience against the negative impact of global climate and land use change. Carbon stock fluxes after wildfires in the area have not yet been quantified. However, the assessment of this and other ecosystem service flows is crucial in contaminated (both radioactively and by unexploded ordnance) landscapes of the CEZ. Aims The aim of this study was to estimate carbon stock losses resulting from the catastrophic 2020 fires in the CEZ using satellite data, as field visitations or aerial surveys are impossible due to the ongoing war. Methods The aboveground carbon stock was predicted in a wall-to-wall manner using random forest modelling based on Sentinel data (both optical and synthetic aperture radar or SAR). We modelled the carbon stock loss using the change in Sentinel-1 backscatter before and after the fire events and local combustion factors. Results Random forest models performed well (root-mean-square error (RMSE) of 22.6 MgC·ha−1 or 37% of the mean) to predict the pre-fire carbon stock. The modelled carbon loss was estimated to be 156.3 Gg C (9.8% of the carbon stock in burned forests or 1.5% at the CEZ level). The standalone SAR backscatter delta showed a higher RMSE than the modelled estimate but better systematic agreement (0.90 vs. 0.73). Scots pine (Pinus sylvestris L.)-dominated stands contributed the most to carbon stock loss, with 74% of forests burned in 2020. Conclusion The change in SAR backscatter before and after a fire event can be used as a rough proxy indicator of aboveground carbon stock loss for timely carbon map updating. The model using SAR backscatter change and backscatter values prior to wildfire is able to reliably estimate carbon emissions when on-ground monitoring is impossible

Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE