Zero modes, beta functions and IR/UV interplay in higher-loop QED

We analyze the relation between the short-distance behavior of quantum field theory and the strong-field limit of the background field formalism, for QED effective Lagrangians in self-dual backgrounds, at both one and two loop. The self-duality of the background leads to zero modes in the case of spinor QED, and these zero modes must be taken into account before comparing the perturbative beta function coefficients and the coefficients of the strong-field limit of the effective Lagrangian. At one-loop this is familiar from instanton physics, but we find that at two-loop the role of the zero modes, and the interplay between IR and UV effects in the renormalization, is quite different. Our analysis is motivated in part by the remarkable simplicity of the two-loop QED effective Lagrangians for a self-dual constant background, and we also present here a new independent derivation of these two-loop results.Comment: 15 pages, revtex

Thermodynamic characteristics of the classical n-vector magnetic model in three dimensions

The method of calculating the free energy and thermodynamic characteristics of the classical n-vector three-dimensional (3D) magnetic model at the microscopic level without any adjustable parameters is proposed. Mathematical description is perfomed using the collective variables (CV) method in the framework of the $\rho^4$ model approximation. The exponentially decreasing function of the distance between the particles situated at the N sites of a simple cubic lattice is used as the interaction potential. Explicit and rigorous analytical expressions for entropy,internal energy, specific heat near the phase transition point as functions of the temperature are obtained. The dependence of the amplitudes of the thermodynamic characteristics of the system for $T>T_c$ and $T<T_c$ on the microscopic parameters of the interaction potential are studied for the cases $n=1,2,3$ and $n\to\infty$. The obtained results provide the basis for accurate analysis of the critical behaviour in three dimensions including the nonuniversal characteristics of the system.Comment: 25 pages, 5 figure

Erythropoietin mimetic peptide (pHBSP) corrects endothelial dysfunction in a rat model of preeclampsia

Preeclampsia is a severe disease of late pregnancy. Etiological factors and a pathogenetic pattern of events still require significant clarification, but it is now recognized that a large role is played by placentation disorders and emerging endothelial dysfunction. The administration of short-chain peptides mimicking the spatial structure of the B erythropoietin chain may become one of the directions of searching for new drugs for preeclampsia prevention and therap

Biochemical blood parameters in determining the elastic properties of the vascular wall in hypertensive patients with abdominal obesity

The article describes approaches that use parameters of biochemical laboratory markers as the basis for the indirect determination of the value of a functional parameter 'pulse wave velocity*, which characterizes the stiffness of the vessel wall. Using a mathematical model of an artificial neural network makes it possible to assess the degree of deviation of the resulting stiffness of the vessel wall from the standard value. An increase in this value is determined by the defeat of the vascular wall as a target organ that helps to clarify the stage of hypertension and optimize antihypertensive therapy in hypertensive patients with abdominal obesity.В статье описаны подходы, позволяющие использовать параметры биохимических лаб раторных маркеров в качестве основы для оценки величины функционального параметра «скорость распространения пульсовой волны», характеризующего жесткость сосудистой стенки. Использование математической модели искусственной нейронной сети дает возможность оценить степень отклонения полученного показателя жесткости сосудистой стенки от нормативного значения. При повышении этого значения определяется поражение сосудистой стенки как органа-мишени, что позволяет уточнить стадию артериальной гипертонии и провести оптимизацию антигипертензивной терапии у больных артериальной гипертонией с абдоминальным ожирением

Multifunctionality of silver closo-boranes

Silver compounds share a rich history in technical applications including photography, catalysis, photocatalysis, cloud seeding and as antimicrobial agents. Here we present a class of silver compounds (Ag2B10H10 and Ag2B12H12) that are semiconductors with a bandgap at 2.3?eV in the green visible light spectrum. The silver boranes have extremely high ion conductivity and dynamic-anion facilitated Ag(+) migration is suggested based on the structural model. The ion conductivity is enhanced more than two orders of magnitude at room temperature (up to 3.2?mS?cm(-1)) by substitution with AgI to form new compounds. Furthermore, the closo-boranes show extremely fast silver nano-filament growth when excited by electrons during transmission electron microscope investigations. Ag nano-filaments can also be reabsorbed back into Ag2B12H12. These interesting properties demonstrate the multifunctionality of silver closo-boranes and open up avenues in a wide range of fields including photocatalysis, solid state ionics and nano-wire production

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 anomalous t t-bar production in the highly-boosted all-hadronic final state

A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu

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

Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO

The study of the dynamics of clinical and laboratory-instrumental parameters in hypertensive patients with obesity who underwent COVID-19-associated pneumonia

BACKGROUND: According  to the results of the ESSE-RF study, the frequency of obesity in the population  reached 29.7%. Obesity is one of the main risk factors for the development of cardiovascular diseases. Features of the course of COVID-19 in patients with obesity is a very urgent problem.AIM: The aim of the study was a comparative investigation of clinical and laboratory-instrumental parameters in AH patients with or without obesity who had COVID-19 associated pneumonia, to identify the role of obesity as a potential predictor of post-COVID cardiovascular complications 3 months after discharge from the hospital.MATERIALS AND METHODS: Materials and methods. The study included 174 patients with COVID-19-associated pneumonia. Group 1 included 78 patients with AH without obesity, group 2 — 96 patients with AH and obesity. All patients were tested with a blood sample at the time of admission and 3 months after discharge from the hospital. We assessed parameters of general blood test, biochemistry, hemostasis, inflammation biomarkers — concentration of C-reactive protein (CRP), highly sensitive CRP (hs-CRP), homocysteine, IL-6, etc. All patients initially underwent computed tomography  of the chest. In both groups, 24-hour blood pressure monitoring was performed using BPLaB device, according to the standard protocol; echocardiography using  an expert class ultrasound diagnostic  system Vivid S70. The study is registered with the Clinical Trials.gov database Identifier: NCT04501822.RESULTS: Results. The biomarker that significantly distinguished the both groups of patients, as well as subgroups according to the degree of obesity was the concentration of maxCRP and hs-CRP, which was significantly higher in group 2. In addition, the registered maximum values of MPO, NT-proBNP, IL-1,6, TNA-α and NRL parameters in group 2 of patients with 2–3 degrees of obesity, may indicate the highest probability of developing  delayed adverse cardiovascular complications  in this group of patients. Mean systolic blood pressure, variability of systolic and diastolic blood pressure, and heart rate at night were significantly  higher in AH patients with obesity. Numerous correlations of obesity with laboratory and instrumental parameters have been registered, which may indicate an increased likelihood of delayed unwanted cardiovascular complications in this particular group of patients. Multiple regression showed that obesity is an independent predictor of an increase in LDH, hs-CRP and right atrium.CONCLUSION: Dynamic control of the studied parameters in patients with AH and OB registered an increased concentration of CRP at the initial stage and 3 months after treatment, with a general trend towards a decrease in the increased initial structural parameters of ECHO CG. The logistic regression method showed that the presence of OB in patients with AH is an independent factor causing increased levels of immune inflammation (CRP), a marker of tissue destruction (LDH), and load on the right atrium