Classical approach in quantum physics

The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom recently discovered with the help of Poincar$\acute{\mathrm{e}}$ section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treating as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormgroup symmetry, criterion of accuracy and so on are reviewed as well. In conclusion, the relation between quantum theory, classical physics and measurement is discussed.Comment: This review paper was rejected from J.Phys.A with referee's comment "The author has made many worthwhile contributions to semiclassical physics, but this article does not meet the standard for a topical review"

Electron recombination with multicharged ions via chaotic many-electron states

We show that a dense spectrum of chaotic multiply-excited eigenstates can play a major role in collision processes involving many-electron multicharged ions. A statistical theory based on chaotic properties of the eigenstates enables one to obtain relevant energy-averaged cross sections in terms of sums over single-electron orbitals. Our calculation of the low-energy electron recombination of Au$^{25+}$ shows that the resonant process is 200 times more intense than direct radiative recombination, which explains the recent experimental results of Hoffknecht {\em et al.} [J. Phys. B {\bf 31}, 2415 (1998)].Comment: 9 pages, including 1 figure, REVTe

Amperometic microsensor for measurement of gaseous and dissolved CO2

A simple method to measure dissolved CO2 at a microscale would be beneficial for many scientific and medical applications. A simple amperometic microsensor for CO2 with a 20-100 µm wide tip was developed by placing a layer of acidic O2 trap solution containing Cr2+ in front of a Clark-type electrochemical sensor. The Clark-type sensor contains a Ag cathode in an ionic liquid, and also a Ag guard cathode behind the sensing cathode to prevent interference from reducible contaminants in the ionic liquid. The constructed sensors exhibited linear response over relatively large intervals of CO2 partial pressure, but for CO2 partial pressures of < 20 Pa the response was only about 60% of that observed at 20-1000 Pa. The slope of the calibration curve at 2-6 kPa was about 80% of the slope from 0-1 kPa. A high baseline signal caused by water diffusing through the membrane into the ionic liquid was avoided by making very conical sensors so that the water concentration around the cathode was kept low by diffusional transport into the bulk reservoir of ionic liquid, but elevated zero currents by a factor of about two was often observed for sensors more than 1 month old. The lifetime of the sensor by continuous operation can be more than 4 months, but with a slow decrease in sensitivity that may be caused by lower membrane permeability. Use of the sensor was demonstrated by measuring CO2 dynamics in the thallus of a red algae along with variations in O2 and pH

Clinical evaluation of a multiplex PCR-based test for joint infection:a prospective diagnostic accuracy study of forty-nine patients

Purpose: The purpose of this study was to evaluate the diagnostic accuracy (sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV)) of the PCR-based BioFire® Joint Infection Panel (BJI Panel) against microbiological culture growth for patients suspected of having a native or prosthetic joint infection. Methods: Synovial fluid and tissue biopsies were prospectively collected from patients from June 2022 to June 2023. The results of the BJI Panel were compared with those of culture growth. Results: 51 samples were included. Including all pathogens, the sensitivity was 69%, the specificity 89%, the PPV 73% and the NPV 86%. Including only pathogens in the BJI Panel, the sensitivity was 100%, the specificity 90%, the PPV 73% and the NPV 100%. Conclusion: The BJI Panel has a high accuracy for detecting the pathogens in its panel, but the absence of important common pathogens from the panel reduces its sensitivity and NPV. With a short turnaround time and precise pathogen detection, the BJI Panel has the potential to add value as a complementary diagnostic method.</p

Correlated Two Electron Effects in Collisions of Multiply Charged Au Ions with He

We have studied the fate of electrons released in collisions between highly charged Au/sup q+/ ions (20 MeV) and He atoms and find that the large transfer ionization (TI) cross section observed can be accounted for by transfer of two electrons to a highly correlated state on the Au projectile followed by the loss of one electron to the continuum. Autoionization lines are also observed, but they are attributable to electron transfer accompanied by core excitation (TE)

Measurement of charm production at central rapidity in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV

The $p_{\rm T}$-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D$^0$, D$^+$, and D$^{*+}$ in the rapidity range $|y|<0.5$, and for transverse momentum $1< p_{\rm T} <12$ GeV/$c$, were measured in proton-proton collisions at $\sqrt{s} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D$^0 \rightarrow$K$\pi$, D$^+ \rightarrow$K$\pi\pi$, D$^{*+} \rightarrow$D$^0\pi$, and their charge conjugates, and was performed on a $L_{\rm int} = 1.1$ nb$^{-1}$ event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at $\sqrt{s} = 2.76$ TeV and at 7 TeV was evaluated by extrapolating to the full phase space the $p_{\rm T}$-differential production cross sections at $\sqrt{s} = 2.76$ TeV and our previous measurements at $\sqrt{s} = 7$ TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/307

The contribution of the four-parton final states to gamma* gamma* -> hadrons

In the analysis of the total cross section for the gamma* gamma* -> hadrons process, we include the four parton final states, which are part of the O(alpha_s^2) corrections. The four-parton final states contain the diagrams with gluon exchange in the crossed channel, which constitute the leading order of the BFKL resummation. We show that the diagrams with gluon exchange in the crossed channel play an important role in the large Y region, however their contribution to the cross section must be evaluated exactly. In fact, the high-energy limit, which constitutes the kinematic framework of the BFKL resummation, is not sufficiently accurate at LEP2 energies. The inclusion of the diagrams with gluon exchange in the crossed channel reduces the discrepancy between the theory and the LEP2 data collected by the L3 Collaboration, but the data still lie above the theory, even allowing for a large scale uncertainty in the theory. Thus, in order to describe accurately the data for gamma* gamma* -> hadrons in the large Y region, corrections of an order higher than O(alpha_s^2) seem to be necessary.Comment: 32 pages, 10 figures, published versio

Roadmap on dynamics of molecules and clusters in the gas phase

This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty order of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity from the smallest (diatomic) molecules to clusters and nanoparticles. Combining some of these techniques opens up new avenues to unravel hitherto unexplored reaction pathways and mechanisms, and to establish their significance in, e.g. radiotherapy and radiation damage on the nanoscale, astrophysics, astrochemistry and atmospheric science

European Academy of Neurology (EAN) guideline on the management of amyotrophic lateral sclerosis in collaboration with European Reference Network for Neuromuscular Diseases (ERN EURO-NMD)

Background This update of the guideline on the management of amyotrophic lateral sclerosis (ALS) was commissioned by the European Academy of Neurology (EAN) and prepared in collaboration with the European Reference Network for Neuromuscular Diseases (ERN EURO-NMD) and the support of the European Network for the Cure ALS (ENCALS) and the European Organization for Professionals and Patients with ALS (EUpALS). Methods Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was used to assess the effectiveness of interventions for ALS. Two systematic reviewers from Cochrane Response supported the guideline panel. The working group identified a total of 26 research questions, performed systematic reviews, assessed the quality of the available evidence, and made specific recommendations. Expert consensus statements were provided where insufficient evidence was available. Results A guideline mapping effort revealed only one other ALS guideline that used GRADE methodology (a National Institute for Health and Care Excellence [NICE] guideline). The available evidence was scarce for many research questions. Of the 26 research questions evaluated, the NICE recommendations could be adapted for 8 questions. Other recommendations required updates of existing systematic reviews or de novo reviews. Recommendations were made on currently available disease-modifying treatments, multidisciplinary care, nutritional and respiratory support, communication aids, psychological support, treatments for common ALS symptoms (e.g., muscle cramps, spasticity, pseudobulbar affect, thick mucus, sialorrhea, pain), and end-of-life management. Conclusions This update of the guideline using GRADE methodology provides a framework for the management of ALS. The treatment landscape is changing rapidly, and further updates will be prepared when additional evidence becomes available