KINETICS OF HYDROGEN- INDUCED DIFFUSION PHASE TRANSFORMATIONS IN Y2Fe17 ALLOY

Исследована кинетика роста новых фаз в ходе индуцированных водородом прямого и обратного фазовых превращений в сплаве Y2Fe17. Показано, что развитие как прямого, так и обратного фазовых превращений замедляется с понижением температуры обработки. Построены изотермические кинетические диаграммы прямого и обратного фазового превращений. Установлено, что данные превращения протекают по механизму зарождения и роста, рассчитаны значения энергии их активации.There has been investigated kinetics of growth of new phases during hydrogen-induced direct and reverse phase transformation in Y2Fe17 alloy. It is shown that evolution of these phase transformations decrease with temperature transformation decreasing. It was determined that these phase transformations proceed by mechanism of nucleation and growth. It was built isothermal kinetic diagrams of both the direct and reverse phase transformations and established the activation energy values for these hydrogen-induced phase transformations

ANALYSIS OF HYDROGEN-INDUCED DIRECT PHASE TRANSFORMATION KINETICS IN Y2FE17 ALLOY ON THE BASE OF KOLMOGOROV'S MODEL

Кинетика индуцированного водородом прямого фазового превращения в магнитотвердом сплаве Y2Fe17 проанализирована в рамках кинетической модели Колмогорова. Установлено, что индуцированное водородом прямое фазовое превращение в магнитотвердом сплаве Y2Fe17 классифицируется как диффузионно-контролируемое превращение, реализующееся по механизму зарождения и роста с убывающей скоростью зарождения центров новых фаз − -Fe и YH2. На основе кинетической теории фазовых превращений Колмогорова получено кинетическое уравнение, хорошо описывающее изотермические кинетические кривые фазового превращения в сплаве Y2Fe17 в зависимости от температуры превращения.inetics of the hydrogen induced direct phase transformation in Y2Fe17 hard magnetic alloy has been analyzed in framework of Kolmogorov's kinetic model. It is established that hydrogen induced direct phase transformation in Y2Fe17 hard magnetic alloy classified as diffusion controlled transformation which occurs by mechanism of nucleation and growth with decreasing nucleation rate of new phases − α-Fe and YH2. On the base of Kolmogorov's kinetic theory of the phase transformations has been obtained kinetic equation that well described the isothermal kinetic curves of phase transformation in Y2Fe17 alloy depending on transformation temperature

Incidence of pancreatic malignancies in the Russian Federation: a retrospective cohort trial

Background. Pancreatic malignancies pose a challenging medical and social problem. The assessment of oncology care requires an in-depth analysis of morbidity and lethality. At a relatively improved prevalence and lethality in other-locale malignancies, pancreatic cancer remains a disappointing situation. Medical statistics in pancreatic malignancy can be used for the specialty care prediction and implementation of measures to advance diagnostic algorithms and population screening.Objectives. An assessment of the pancreatic malignancy incidence and mortality in the adult population of Russian Federation over a six-year period.Methods. A retrospective descriptive cohort trial included statistical data on morbidity and mortality in pancreatic cancer patients (C 25.0-C 25.9) according to the ICD of 10th edition. A comparison cohort sampled patients with all-locale neoplasms (C00-C96) according to the ICD of 10th edition, excluding nosologies C25.0-C25.9. Information was sourced in the Federal Statistical Abstracts for the period of 2014-2019. Inclusion criteria: the study cohort included pancreatic cancer patients diagnosed at the age of 18 years on, and comparison cohort — malignancy patients diagnosed with at 18 years on. The main study indicator were the pancreatic cancer morbidity and mortality figures in Russia.Results. Pancreatic cancer was shown to co-increase main morbidity figures in 2014-2019 compared to malignant neoplasms of other localities. Other-locale malignancies decreased mortality over the study period, which was not the case with pancreatic cancer. The period exhibits more frequent morphologically verified diagnoses and higher population numbers registered with specialty dispensaries. Registered pancreatic cancer figures are significantly higher in the female population. The proportion of advanced pancreatic malignancies at primary diagnosis exceeds that of early stages.Conclusion. The findings expose a demand for improving the system of early pancreatic cancer detection via intensifying preventive measures to capture the patient’s predisposition and screening techniques for early disease diagnosis. An active outpatient surveillance is prerequisite to an effective population involvement in dispensary screening

Pore timing:the evolutionary origins of the nucleus and nuclear pore complex

The name “eukaryote” is derived from Greek, meaning “true kernel”, and describes the domain of organisms whose cells have a nucleus. The nucleus is thus the defining feature of eukaryotes and distinguishes them from prokaryotes (Archaea and Bacteria), whose cells lack nuclei. Despite this, we discuss the intriguing possibility that organisms on the path from the first eukaryotic common ancestor to the last common ancestor of all eukaryotes did not possess a nucleus at all—at least not in a form we would recognize today—and that the nucleus in fact arrived relatively late in the evolution of eukaryotes. The clues to this alternative evolutionary path lie, most of all, in recent discoveries concerning the structure of the nuclear pore complex. We discuss the evidence for such a possibility and how this impacts our views of eukaryote origins and how eukaryotes have diversified subsequent to their last common ancestor

Combined searches for the production of supersymmetric top quark partners in proton–proton collisions at √s=13Te

A combination of searches for top squark pair production using proton–proton collision data at a center-of-mass energy of 13TeV at the CERN LHC, corresponding to an integrated luminosity of 137fb$^{-1}$ collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on the model, the combined result excludes a top squark mass up to 1325GeV for a massless neutralino, and a neutralino mass up to 700GeV for a top squark mass of 1150GeV. Top squarks with masses from 145 to 295GeV, for neutralino masses from 0 to 100GeV, with a mass difference between the top squark and the neutralino in a window of 30GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420GeV

A search for new physics in central exclusive production using the missing mass technique with the CMS detector and the CMS-TOTEM precision proton spectrometer

A generic search is presented for the associated production of a Z boson or a photon with an additional unspecified massive particle X, pp → pp + Z/γ + X, in proton-tagged events from proton–proton collisions at √s = 13 TeV, recorded in 2017 with the CMS detector and the CMS-TOTEM precision proton spectrometer. The missing mass spectrum is analysed in the 600–1600 GeV range and a fit is performed to search for possible deviations from the background expectation. No significant excess in data with respect to the background predictions has been observed. odelindependent upper limits on the visible production cross section of pp → pp + Z/γ + X are set

Search for a right-handed W boson and a heavy neutrino in proton-proton collisions at s \sqrt{s} = 13 TeV

A search is presented for a right-handed W boson (WR) and a heavy neutrino (N), in a final state consisting of two same-flavor leptons (ee or μμ) and two quarks. The search is performed with the CMS experiment at the CERN LHC using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138 fb−1. The search covers two regions of phase space, one where the decay products of the heavy neutrino are merged into a single large-area jet, and one where the decay products are well separated. The expected signal is characterized by an excess in the invariant mass distribution of the final-state objects. No significant excess over the standard model background expectations is observed. The observations are interpreted as upper limits on the product of WR production cross sections and branching fractions assuming that couplings are identical to those of the standard model W boson. For N masses mN equal to half the WR mass mWR (mN = 0.2 TeV), mWR is excluded at 95% confidence level up to 4.7 (4.8) and 5.0 (5.4) TeV for the electron and muon channels, respectively. This analysis provides the most stringent limits on the WR mass to date

Search for flavor-changing neutral current interactions of the top quark and the Higgs boson decaying to a bottom quark-antiquark pair at s√ = 13 TeV

A search for flavor-changing neutral current interactions of the top quark (t) and the Higgs boson (H) is presented. The search is based on a data sample corresponding to an integrated luminosity of 137 fb−1 recorded by the CMS experiment at the LHC in proton-proton collisions at s√ = 13 TeV. Events containing exactly one lepton (muon or electron) and at least three jets, among which at least two are identified as originating from the hadronization of a bottom quark, are analyzed. A set of deep neural networks is used for kinematic event reconstruction, while boosted decision trees distinguish the signal from the background events. No significant excess over the background predictions is observed, and upper limits on the signal production cross sections are extracted. These limits are interpreted in terms of top quark decay branching fractions (B ) to the Higgs boson and an up (u) or a charm quark (c). Assuming one nonvanishing extra coupling at a time, the observed (expected) upper limits at 95% confidence level are B (t → Hu) < 0.079 (0.11)% and B (t → Hc) < 0.094 (0.086)%