Clinical cases of microscopic colitis: Diagnosis and treatment issues. Case report

Currently, there is an increase in the incidence of microscopic colitis. There are difficulties in diagnosing this disease due to the variability of histological signs, variability of morphological changes in the mucous membrane of the colon in different parts of the colon, and the combination in one patient of not only various forms of microscopic colitis, but also other intestinal diseases. The article describes the differential diagnosis, an example of its staging and successful treatment of various forms of microscopic colitis with budesonide (two clinical cases presented)

The possibilities of quantitative analysis of the relationship between the severity of the COVID-19 pandemic and the institutional characteristics of the countries of the world

The interrelation of the severity of the epidemiological situation in a particular country and its institutional characteristics (including the level of health care, quality of management, the level of public trust, cultural characteristics, etc.) is considered. As a result, using the developed index of the severity of the epidemiological situation, the institutional characteristics that most affect the effectiveness of the measures applied were determined. It was figured out that of the 16 characteristics considered, only two (the level of employment and trust in the government) have a medium statistical correlation with the severity of the pandemic. Three more characteristics (prevalence of secular-rational values, degree of urbanization, GDP PPP per capita) have a correlation close to the medium. The remaining characteristics (including health care costs, government efficiency, etc.) have either a weak correlation wiыth severity, or actually do not have it. The results obtained indicate insufficient use and reassessment of existing institutional capacities at the initial stage of the pandemic, as well as insufficient reliability of morbidity and mortality statistics in a number of countries. In conclusion, based on the analysis of statistical indicators, recommendations are given to improve the effectiveness of the use of institutional capacity to counter epidemiological threats, improve this potential, increase the effectiveness of protective and restrictive measures that reduce the severity of the epidemiological situation

Observation of the Decay Λ0b→Λ+cτ−¯ν

The first observation of the semileptonic b-baryon decay Λb0→Λc+τ-ν¯τ, with a significance of 6.1σ, is reported using a data sample corresponding to 3 fb-1 of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The τ- lepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+π-π+π-) is measured to be 2.46±0.27±0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λb0→Λc+τ-ν¯τ)=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Λb0→Λc+π-π+π-. The ratio of semileptonic branching fractions R(Λc+)B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+μ-ν¯μ) is derived to be 0.242±0.026±0.040±0.059, where the external branching fraction uncertainty from the channel Λb0→Λc+μ-ν¯μ contributes to the last term. This result is in agreement with the standard model prediction

Observation of the doubly charmed baryon decay Ξcc++→Ξc′+π+

The Ξcc++→Ξc′+π+ decay is observed using proton-proton collisions collected by the LHCb experiment at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−1. The Ξcc++→Ξc′+π+ decay is reconstructed partially, where the photon from the Ξc′+→Ξc+γ decay is not reconstructed and the pK−π+ final state of the Ξc+ baryon is employed. The Ξcc++→Ξc′+π+branching fraction relative to that of the Ξcc++→Ξc+π+ decay is measured to be 1.41 ± 0.17 ± 0.10, where the first uncertainty is statistical and the second systematic. [Figure not available: see fulltext.

Study of charmonium and charmonium-like contributions in B+ → J/ψηK+ decays

A study of B+→ J/ψηK+ decays, followed by J/ψ → μ+μ− and η → γγ, is performed using a dataset collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The J/ψη mass spectrum is investigated for contributions from charmonia and charmonium-like states. Evidence is found for the B+→ (ψ2(3823) → J/ψη)K+ and B+→ (ψ(4040) → J/ψη)K+ decays with significance of 3.4 and 4.7 standard deviations, respectively. This constitutes the first evidence for the ψ2(3823) → J/ψη decay

Searches for rare Bs0 and B 0 decays into four muons

Searches for rare Bs0 and B0 decays into four muons are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. Direct decays and decays via light scalar and J/ψ resonances are considered. No evidence for the six decays searched for is found and upper limits at the 95% confidence level on their branching fractions ranging between 1.8 × 10−10 and 2.6 × 10−9 are set. [Figure not available: see fulltext.

Observation of the B0→¯D*0K+π− and B0s→¯D*0K−π+ decays

The first observations of B0→D¯∗(2007)0K+π- and Bs0→D¯∗(2007)0K-π+ decays are presented, and their branching fractions relative to that of the B0→D¯∗(2007)0π+π- decay are reported. These modes can potentially be used to investigate the spectroscopy of charm and charm-strange resonances and to determine the angle γ of the Cabibbo-Kobayashi-Maskawa unitarity triangle. It is also important to understand them as a source of potential background in determinations of γ from B+→DK+ and B0→DK+π- decays. The analysis is based on a sample corresponding to an integrated luminosity of 5.4 fb-1 of proton-proton collision data at 13 TeV center-of-mass energy recorded with the LHCb detector. The D¯∗(2007)0 mesons are fully reconstructed in the D¯0π0 and D¯0γ channels with the D¯0→K+π- decay. A novel weighting method is used to subtract background while simultaneously applying an event-by-event efficiency correction to account for resonant structures in the decays

Angular analysis of D0→π+π−μ+μ−D^0 \to \pi^+\pi^-\mu^+\mu^- and D0→K+K−μ+μ−D^0 \to K^+K^-\mu^+\mu^- decays and search for CPCP violation

The first full angular analysis and an updated measurement of the decay-rate $CP$ asymmetry of the $D^0 \to \pi^+\pi^-\mu^+\mu^-$ and $D^0 \to K^+K^-\mu^+\mu^-$ decays are reported. The analysis uses proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. The data set corresponds to an integrated luminosity of 9 fb$^{-1}$. The full set of $CP$-averaged angular observables and their $CP$ asymmetries are measured as a function of the dimuon invariant mass. The results are consistent with expectations from the standard model and with $CP$ symmetry.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-035.html (LHCb public pages

Tests of lepton universality using B0→KS0ℓ+ℓ−B^0\to K^0_S \ell^+ \ell^- and B+→K∗+ℓ+ℓ−B^+\to K^{*+} \ell^+ \ell^- decays

Tests of lepton universality in $B^0\to K^0_S \ell^+ \ell^-$ and $B^+\to K^{*+} \ell^+ \ell^-$ decays where $\ell$ is either an electron or a muon are presented. The differential branching fractions of $B^0\to K^0_S e^+ e^-$ and $B^+\to K^{*+} e^+ e^-$ decays are measured in intervals of the dilepton invariant mass squared. The measurements are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of $9\, \mathrm{fb}^{-1}$. The results are consistent with the Standard Model and previous tests of lepton universality in related decay modes. The first observation of $B^0 \to K^0_S e^+ e^-$ and $B^+ \to K^{*+} e^+ e^-$ decays is reported

Study of B-c(+) decays to charmonia and three light hadrons

Abstract Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1 collected with the LHCb detector, seven decay modes of the $${\mathrm{B}}_{\mathrm{c}}^{+}$$ B c + meson into a J/ψ or ψ(2S) meson and three charged hadrons, kaons or pions, are studied. The decays $${\mathrm{B}}_{\mathrm{c}}^{+}$$ B c + → (ψ(2S) → J/ψπ+π−)π+, $${\mathrm{B}}_{\mathrm{c}}^{+}$$ B c + → ψ(2S)π+π−π+, $${\mathrm{B}}_{\mathrm{c}}^{+}$$ B c + → J/ψK+π−π+ and $${\mathrm{B}}_{\mathrm{c}}^{+}$$ B c + → J/ψK+K−K+ are observed for the first time, and evidence for the $${\mathrm{B}}_{\mathrm{c}}^{+}$$ B c + → ψ(2S)K+K−π+, decay is found, where J/ψ and ψ(2S) mesons are reconstructed in their dimuon decay modes. The ratios of branching fractions between the different $${\mathrm{B}}_{\mathrm{c}}^{+}$$ B c + decays are reported as well as the fractions of the decays proceeding via intermediate resonances. The results largely support the factorisation approach used for a theoretical description of the studied decays.</jats:p