NEW PROPOSALS FOR THE REACTION e+e−→π+π−π0

1994 ◽  
Vol 09 (04) ◽  
pp. 527-545 ◽  
Author(s):  
N.N. ACHASOV ◽  
A.A. KOZHEVNIKOV
Keyword(s):  
Mass Spectrum ◽  
Cross Section ◽  
Imaginary Part ◽  
Experimental Studies ◽  
Triangle Diagram ◽  
Additional Information ◽  
G Parity ◽  
The Difference ◽  
Ozi Rule ◽  
Self Consistency

The influence of the singularity of the triangle diagram on patterns of ρω interference in the π+π− mass spectrum of the reaction e+e−→π+π−π0 is considered at energies in the range [Formula: see text]. This influence arises due to the difference between the phases of the ω→ρπ and ρ→ωπ transition amplitudes implied by the imaginary part of this diagram. The decay kinematics of the triangle diagram results in the distortion of the π+π− mass spectrum. Taking this diagram into account at energies in between ω and φ peaks implies the measurable decrease of the cross section. Experimental studies of the effect of the imaginary part of the triangle diagram at e+e− colliders with the luminosity L=1031 cm −2 s −1 or higher could be of great interest as a tool for testing the self-consistency of calculations going beyond the tree approximation and as the possibility of obtaining additional information on the mechanism of breaking of the OZI rule and G parity.

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

scholarly journals Hydraulic Transients in Viscoelastic Pipeline System with Sudden Cross-Section Changes

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4071
Author(s):  
Michał Kubrak ◽  
Agnieszka Malesińska ◽  
Apoloniusz Kodura ◽  
Kamil Urbanowicz ◽  
Michał Stosiak
Keyword(s):  
Numerical Model ◽  
Cross Section ◽  
Laboratory Data ◽  
Experimental Studies ◽  
Distribution Networks ◽  
Water Hammer ◽  
Fluid Distribution ◽  
Pipeline System ◽  
Hydraulic Transients ◽  
Single Pipe

It is well known that the water hammer phenomenon can lead to pipeline system failures. For this reason, there is an increased need for simulation of hydraulic transients. High-density polyethylene (HDPE) pipes are commonly used in various pressurised pipeline systems. Most studies have only focused on water hammer events in a single pipe. However, typical fluid distribution networks are composed of serially connected pipes with various inner diameters. The present paper aims to investigate the influence of sudden cross-section changes in an HDPE pipeline system on pressure oscillations during the water hammer phenomenon. Numerical and experimental studies have been conducted. In order to include the viscoelastic behaviour of the HDPE pipe wall, the generalised Kelvin–Voigt model was introduced into the continuity equation. Transient equations were numerically solved using the explicit MacCormack method. A numerical model that involves assigning two values of flow velocity to the connection node was used. The aim of the conducted experiments was to record pressure changes downstream of the pipeline system during valve-induced water hammer. In order to validate the numerical model, the simulation results were compared with experimental data. A satisfactory compliance between the results of the numerical calculations and laboratory data was obtained.

scholarly journals Photoionization Cross-Sections of Carbon-Like N+ Near the K-Edge (390–440 eV)

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 27
Author(s):  
Jean-Paul Mosnier ◽  
Eugene T. Kennedy ◽  
Jean-Marc Bizau ◽  
Denis Cubaynes ◽  
Ségolène Guilbaud ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Cross Sections ◽  
Experimental Studies ◽  
Photoionization Cross Section ◽  
Theoretical Work ◽  
Rydberg Series ◽  
R Matrix ◽  
Resonance Strengths ◽  
Nitrogen Ion

High-resolution K-shell photoionization cross-sections for the C-like atomic nitrogen ion (N+) are reported in the 398 eV (31.15 Å) to 450 eV (27.55 Å) energy (wavelength) range. The results were obtained from absolute ion-yield measurements using the SOLEIL synchrotron radiation facility for spectral bandpasses of 65 meV or 250 meV. In the photon energy region 398–403 eV, 1s⟶2p autoionizing resonance states dominated the cross section spectrum. Analyses of the experimental profiles yielded resonance strengths and Auger widths. In the 415–440 eV photon region 1s⟶(1s2s22p2 4P)np and 1s⟶(1s2s22p2 2P)np resonances forming well-developed Rydberg series up n=7 and n=8 , respectively, were identified in both the single and double ionization spectra. Theoretical photoionization cross-section calculations, performed using the R-matrix plus pseudo-states (RMPS) method and the multiconfiguration Dirac-Fock (MCDF) approach were bench marked against these high-resolution experimental results. Comparison of the state-of-the-art theoretical work with the experimental studies allowed the identification of new resonance features. Resonance strengths, energies and Auger widths (where available) are compared quantitatively with the theoretical values. Contributions from excited metastable states of the N+ ions were carefully considered throughout.

scholarly journals Extracting Hypernuclear Properties from the (e, e′K+) Cross Section

Particles ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 194-204
Author(s):  
Omar Benhar
Keyword(s):  
Cross Section ◽  
Experimental Studies ◽  
Strong Interactions ◽  
Many Body ◽  
Kaon Production ◽  
Many Body Theory ◽  
Independent Analysis ◽  
Dense Nuclear Matter ◽  
Proton Knockout ◽  
Comprehensive Framework

Experimental studies of hypernuclear dynamics, besides being essential for the understanding of strong interactions in the strange sector, have important astrophysical implications. The observation of neutron stars with masses exceeding two solar masses poses a serious challenge to the models of hyperon dynamics in dense nuclear matter, many of which predict a maximum mass incompatible with the data. In this paper, it is argued that valuable new insight can be gained from the forthcoming extension of the experimental studies of kaon electro production from nuclei to include the 208Pb(e,e′K+)Λ208Tl process. A comprehensive framework for the description of kaon electro production, based on factorization of the nuclear cross section and the formalism of the nuclear many-body theory, is outlined. This approach highlights the connection between the kaon production and proton knockout reactions, which will allow us to exploit the available 208Pb(e,e′p)207Tl data to achieve a largely model-independent analysis of the measured cross section.

scholarly journals Urinary Microbiome Characteristics in Female Patients with Acute Uncomplicated Cystitis and Recurrent Cystitis

2021 ◽  
Vol 10 (5) ◽  
pp. 1097
Author(s):  
Jeong-Ju Yoo ◽  
Hee Shin ◽  
Ju Song ◽  
Minjung Kim ◽  
Jina Yun ◽  
...  
Keyword(s):  
Urine Culture ◽  
Culture Methods ◽  
Microbiome Composition ◽  
Additional Information ◽  
Transurethral Catheter ◽  
Urinary Microbiome ◽  
Acute Uncomplicated Cystitis ◽  
The Difference ◽  
Uncomplicated Cystitis ◽  
Recurrent Cystitis

Traditionally, the diagnostic mainstay of recurrent urinary tract infection has been urinary culture. However, the causative uropathogen of recurrent cystitis has not been well established. Urine DNA next-generation sequencing (NGS) can provide additional information on these infections. Herein, we compared urine NGS results and urine cultures in patients with acute uncomplicated cystitis (AUC) and recurrent cystitis (RC), and evaluated the difference in microbiome patterns in the NGS results. Patients who underwent urine culture and NGS due to AUC or RC were retrospectively reviewed. All urine samples were collected via a transurethral catheter and studied utilizing a type of NGS called 16S ribosomal RNA gene amplification and sequencing. The sensitivity of urine NGS was significantly higher than that of conventional urine culture (69.0% vs. 16.7%, p < 0.05). The detection rate of urine NGS was slightly lower in the RC group than in the AUC group (67.7% vs. 72.7%). Microbiome diversity was significantly higher in the RC group compared to the AUC group (p = 0.007), and the microbiome composition was significantly different between the AUC and RC groups. In the urine NGS results, Pseudomonas, Acinetobacter, and Enterobacteriaceae were found in the AUC group, and Sphingomonas, Staphylococcus, Streptococcus, and Rothia spp. were detected in the RC group. Urine NGS can significantly increase the diagnostic sensitivity compared to traditional urine culture methods, especially in RC patients. AUC and RC patients had significant differences in bacterial diversity and patterns. Therefore, recurrent cystitis might be approached from a different perspective.

An investigation of effects of level density models and gamma ray strength functions on cross-section calculations for the production of 90Y, 153Sm, 169Er, 177Lu and 186Re therapeutic radioisotopes via (n,γ) reactions

2019 ◽  
Vol 108 (1) ◽  
pp. 11-17
Author(s):  
Mert Şekerci ◽  
Hasan Özdoğan ◽  
Abdullah Kaplan
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Production Cross Section ◽  
Gamma Ray ◽  
Production Cross ◽  
Level Density ◽  
Experimental Studies ◽  
Level Density Models ◽  
Strength Functions ◽  
Cancer Diseases

Abstract One of the methods used to treat different cancer diseases is the employment of therapeutic radioisotopes. Therefore, many clinical, theoretical and experimental studies are being carried out on those radioisotopes. In this study, the effects of level density models and gamma ray strength functions on the theoretical production cross-section calculations for the therapeutic radioisotopes 90Y, 153Sm, 169Er, 177Lu and 186Re in the (n,γ) route have been investigated. TALYS 1.9 code has been used by employing different level density models and gamma ray strength functions. The theoretically obtained data were compared with the experimental data taken from the literature. The results are presented graphically for better interpretation.

scholarly journals Apical Extrusion of Debris Produced during Continuous Rotating and Reciprocating Motion

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Giselle Nevares ◽  
Felipe Xavier ◽  
Luciana Gominho ◽  
Flávia Cavalcanti ◽  
Marcely Cassimiro ◽  
...  
Keyword(s):  
Cross Section ◽  
Sodium Hypochlorite ◽  
Reciprocating Motion ◽  
Continuous Motion ◽  
Analytical Balance ◽  
Root Canals ◽  
Apical Extrusion ◽  
Final Weight ◽  
The Difference

This study aimed to analyse and compare apical extrusion of debris in canals instrumented with systems used in reciprocating and continuous motion. Sixty mandibular premolars were randomly divided into 3 groups (n=20): the Reciproc (REC), WaveOne (WO), and HyFlex CM (HYF) groups. One Eppendorf tube per tooth was weighed in advance on an analytical balance. The root canals were instrumented according to the manufacturer’s instructions, and standardised irrigation with 2.5% sodium hypochlorite was performed to a total volume of 9 mL. After instrumentation, the teeth were removed from the Eppendorf tubes and incubated at 37°C for 15 days to evaporate the liquid. The tubes were weighed again, and the difference between the initial and final weight was calculated to determine the weight of the debris. The data were statistically analysed using the Shapiro-Wilk, Wilcoxon, and Mann-Whitney tests (α=5%). All systems resulted in the apical extrusion of debris. Reciproc produced significantly more debris than WaveOne (p<0.05), and both systems produced a greater apical extrusion of debris than HyFlex CM (p<0.001). Cross section and motion influenced the results, despite tip standardization.

Detection of polar stratospheric clouds with ERS-2/GOME data

1995 ◽  
Vol 13 (4) ◽  
pp. 395-405
Author(s):  
R. Meerkoetter
Keyword(s):  
Radiative Transfer ◽  
European Research ◽  
Polar Stratospheric Clouds ◽  
Additional Information ◽  
Tropospheric Aerosol ◽  
Ozone Monitoring ◽  
The Difference ◽  
Stratospheric Clouds

Abstract. Based on radiative transfer calculations, it is studied whether polar stratospheric clouds (PSCs) can be detected by the new Global Ozone Monitoring Experiment (GOME) on board the second European Research Satellite (ERS-2) planned to be launched in 1995. It is proposed to identify PSC-covered areas by use of an indicator, the Normalized Radiance Difference (NRD), which relates the difference of two spectral radiances at 0.515 µm and 0.67 µm to one radiance measured in the centre of the oxygen A-band at 0.76 µm. Simulations are carried out for two solar zenith angles, θ=78.5° and θ=86.2°. They indicate that, in presence of PSCs and with increasing solar zenith angles above θ=80°, the NRD decrease to values clearly below those derived under conditions of a cloud-free stratosphere. Results for θ=86.2° show that the method is successful independent of existing tropospheric clouds, of different tropospheric aerosol loadings, and of surface albedos. Results for θ=78.5° illustrate that PSC detection under conditions of smaller solar zenith angles θ80° needs additional information about tropospheric clouds.

Somatosensory and Auditory Brain Stem Conduction after Head Injury: A Comparison with Clinical Features in Prediction of Outcome

Neurosurgery ◽  
1990 ◽  
Vol 26 (2) ◽  
pp. 278-285 ◽  
Author(s):  
Kenneth Lindsay ◽  
Aydin Pasaoglu ◽  
David Hirst ◽  
Gwen Allardyce ◽  
Ian Kennedy ◽  
...  
Keyword(s):  
Head Injury ◽  
Brain Stem ◽  
Evoked Potential ◽  
Predictive Accuracy ◽  
Normal Subjects ◽  
Prediction Of Outcome ◽  
Prognostic Information ◽  
Additional Information ◽  
Auditory Brain Stem ◽  
The Difference

Abstract Evoked potential conduction times in brain stem auditory (BCT) and central somatosensory pathways (CCT) were recorded from 23 normal subjects and 101 patients with severe head injury. Abnormalities in the CCT and the BCT findings correlated with the clinical indices of brain damage (coma score, motor response, pupil response, and spontaneous and reflex eye movements) in the head-injured patients and each correlated with outcome at 6 months from the injury. The CCT in the “best” hemisphere produced the strongest correlation with outcome (P&lt;0.001). The correlation of the CCT with outcome was stronger in the 47 patients examined 2 to 3 days after the injury (P&lt;0.001) compared to the 34 patients examined within 24 hours after the injury (P&lt;0.02). No such difference was noted for the BCT. Serial studies within the first 2 weeks of injury did not show a consistent pattern and repetition of the investigation over this period did not provide any additional information. We used an INDEP-SELECT discriminant analysis program to determine whether information from the evoked potential data could improve prediction of outcome based on clinical data alone. With the addition of the CCT, the predictive accuracy (expressed as the correct classification probability) increased only slightly from 77 to 80%, and the difference was not significant. We conclude that central somatosensory and auditory brain stem conduction times provide useful prognostic information in paralyzed or sedated patients, but when neurological examination is feasible the benefits of evoked potential analysis do not justify the effort involved in data collection.

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