Universal kinetics of imperfect reactions in confinement

Chemical reactions generically require that particles come into contact. In practice, reaction is often imperfect and can necessitate multiple random encounters between reactants. In confined geometries, despite notable recent advances, there is to date no general analytical treatment of such imperfect transport-limited reaction kinetics. Here, we determine the kinetics of imperfect reactions in confining domains for any diffusive or anomalously diffusive Markovian transport process, and for different models of imperfect reactivity. We show that the full distribution of reaction times is obtained in the large confining volume limit from the knowledge of the mean reaction time only, which we determine explicitly. This distribution for imperfect reactions is found to be identical to that of perfect reactions upon an appropriate rescaling of parameters, which highlights the robustness of our results. Strikingly, this holds true even in the regime of low reactivity where the mean reaction time is independent of the transport process, and can lead to large fluctuations of the reaction time - even in simple reaction schemes. We illustrate our results for normal diffusion in domains of generic shape, and for anomalous diffusion in complex environments, where our predictions are confirmed by numerical simulations.

Non-integrable Ising Models in Cylindrical Geometry: Grassmann Representation and Infinite Volume Limit

In this paper, meant as a companion to Antinucci et al. (Energy correlations of non-integrable Ising models: the scaling limit in the cylinder, 2020. arXiv: 1701.05356), we consider a class of non-integrable 2D Ising models in cylindrical domains, and we discuss two key aspects of the multiscale construction of their scaling limit. In particular, we provide a detailed derivation of the Grassmann representation of the model, including a self-contained presentation of the exact solution of the nearest neighbor model in the cylinder. Moreover, we prove precise asymptotic estimates of the fermionic Green’s function in the cylinder, required for the multiscale analysis of the model. We also review the multiscale construction of the effective potentials in the infinite volume limit, in a form suitable for the generalization to finite cylinders. Compared to previous works, we introduce a few important simplifications in the localization procedure and in the iterative bounds on the kernels of the effective potentials, which are crucial for the adaptation of the construction to domains with boundaries.

VHF Omnidirectional Range (VOR) Experimental Positioning for Stratospheric Vehicles

The usage of aeronautical radio-frequency navigational aids can support the future stratospheric aviation as back-up positioning systems. Although GNSS has been extensively redundant in the last years of space operations, radio NavAids can still be supportive of navigation and tracking for novel mission profiles. As an example, in 2016, VHF Omnidirectional Range (VOR) has been proven to work well above its standard service volume limit on a stratospheric balloon flight with the STRATONAV experiment. While VOR provides the “radial” measurement, i.e., the angle between the Magnetic North and the line between the receiver and the transmitting ground station, the intersection of two or more radials at a time allows to perform ground track reconstruction for the vehicle to be tracked. This paper reports the results from the data re-processing from STRATONAV: the acquired radials have been intersected in order to achieve positioning. The radials interfacing method, the position calculation methodology, and the data acquisition strategies from STRATONAV are reported together with the data analysis results.

A finite box as a tool to distinguish free quarks from confinement at high temperatures

Above the pseudocritical temperature $$T_c$$ T c of chiral symmetry restoration a chiral spin symmetry (a symmetry of the color charge and of electric confinement) emerges in QCD. This implies that QCD is in a confining mode and there are no free quarks. At the same time correlators of operators constrained by a conserved current behave as if quarks were free. This explains observed fluctuations of conserved charges and the absence of the rho-like structures seen via dileptons. An independent evidence that one is in a confining mode is very welcome. Here we suggest a new tool how to distinguish free quarks from a confining mode. If we put the system into a finite box, then if the quarks are free one necessarily obtains a remarkable diffractive pattern in the propagator of a conserved current. This pattern is clearly seen in a lattice calculation in a finite box and it vanishes in the infinite volume limit as well as in the continuum. In contrast, the full QCD calculations in a finite box show the absence of the diffractive pattern implying that the quarks are confined.

A méhnyakrák okozta éves epidemiológiai és egészségbiztosítási betegségteher Magyarországon

Összefoglaló. Bevezetés: A méhnyakdaganatok kérdése kiemelten fontos, megoldatlan népegészségügyi probléma. A betegség terhe magas, ami elsősorban az alacsony és közepes jövedelmű országokban élőknél jelentkezik. Célkitűzés: Elemzésünk célja volt meghatározni a méhnyakdaganatok epidemiológiai és egészségbiztosítási betegségterhét Magyarországon a 2018-as évre vonatkoztatva. Adatok és módszerek: Elemzésünket a Nemzeti Egészségbiztosítási Alapkezelő (NEAK) finanszírozási adatbázisának 2018. évi adatai alapján végeztük az in situ (D06), a jóindulatú (D26.0) és a malignus (C53) méhnyakdaganatokra vonatkozóan. Az elemzés a NEAK által finanszírozott összes szolgáltatóra és ellátási formára kiterjed. Meghatároztuk az éves betegszámokat, a prevalenciát 100 000 lakosra, továbbá az éves egészségbiztosítási kiadásokat betegségcsoportonként és korcsoportos bontásban, valamennyi egészségbiztosítási ellátás tekintetében. Eredmények: A NEAK 2018-ban 1,276 milliárd Ft-ot (4,7 millió USD; 4,0 millió EUR) költött a méhnyakdaganatok kezelésére. A betegek és a finanszírozás döntő többsége a méhnyak rosszindulatú daganatához kapcsolható. A finanszírozásból a malignus méhnyakdaganatok részesedése 97%. Ellátási típusonként vizsgálva a legnagyobb kiadási tétel az aktívfekvőbeteg-szakellátásban jelenik meg, éves szinten 763,9 millió Ft, ami az összköltség 59,9%-a. A 100 000 lakosra jutó prevalencia az aktívfekvőbeteg-szakellátás igénybevételi adatai alapján 26/100 000 lakos. Következtetés: A méhnyakdaganatok kezelésének meghatározó költségeleme az aktívfekvőbeteg-szakellátás. Hazánkban a szervezett méhnyakszűrés korszerűsítéseként az új szűrési stratégiát megfelelő finanszírozási támogatással célszerű bevezetni, a szűrővizsgálatoknak, a hozzájuk kapcsolódó további diagnosztikus kivizsgálásnak és terápiának a teljesítményvolumen-korlát alóli mentesítésével. Orv Hetil. 2021; 162(Suppl 1): 22–29. Summary. Introduction: Cervical cancer is a particularly important, unresolved public health problem. The burden of the disease is high, primarily in those living in low- and middle-income countries. Objective: Our aim was to determine the annual epidemiological disease burden and health insurance cost of cervical cancer in Hungary in 2018. Data and methods: Our analysis was made according to the financial database of the National Health Insurance Fund Administration (NHIFA) of Hungary for the year 2018, which covers all service providers and maintenance forms financed by NHIFA. We analysed the in situ (D06), the benignant (D26.0) and the malignant (C53) cervical tumours. The data analysed included annual patient numbers and prevalence of care utilisation per 100 000 population furthermore annual health insurance costs calculated for disease and age groups. Results: In 2018, NHIFA spent 1.276 billion HUF (4.7 million USD, 4.0 million EUR) on the treatment of patients with cervical cancer. The majority of patients and funding can be linked to malignant cervical cancer (97%). Acute inpatient care was the major cost driver: 763.9 million HUF (59.9% of the total health insurance expenditures) annually. The prevalence is 26 per 100 000 population based on acute inpatient care data. Conclusion: Acute inpatient care was the major cost driver. In Hungary, as a modernization of organized cervical screening, it is appropriate to introduce a new screening strategy with appropriate financial support, by exempting screening tests, associated additional diagnostic testing, and therapy from the performance volume limit. Orv Hetil. 2021; 162(Suppl 1): 22–29.

Infinite-Volume Limit of Stochastic s-d System with Single-Component Impurity and s-Electron Spins

A Hamiltonian [Formula: see text], with locally smeared Ising-type s-d exchange between s-electrons and magnetic impurities, in a dilute magnetic alloy, is investigated. The Feynman-Kac theorem, Laplace expansion and Bogolyubov inequality are applied to obtain a lower and upper bound (lb and ub) on the system’s free energy per conducting electron [Formula: see text]. The two bounds differ, in the infinite-volume limit by a term [Formula: see text], linear in impurity concentration: lb[Formula: see text], ub[Formula: see text], [Formula: see text] denoting the Hamiltonian of the approximating mean-field s-d system. [Formula: see text] represents randomly positioned impurities interacting with a mean field implemented by the gas of conduction s-electrons, the latter interacting with the field of barriers and wells (according to the s-electron’s spin orientation) localized at the impurity sites. The inequality [Formula: see text] demonstrates increasing accuracy of the mean-field [Formula: see text]-theory, with decreasing impurity concentration.

Bag-Valve-Mask versus Laryngeal Mask Airway Ventilation in Cardiopulmonary Resuscitation with Continuous Compressions: A Simulation Study

Introduction: The 2017 International Liaison Committee on Resuscitation (ILCOR) guideline recommends that Emergency Medical Service (EMS) providers can perform cardiopulmonary resuscitation (CPR) with synchronous or asynchronous ventilation until an advanced airway has been placed. In the current literature, limited data on CPR performed with continuous compressions and asynchronous ventilation with bag-valve-mask (BVM) are available. Study Objective: In this study, researchers aimed to compare the effectiveness of asynchronous BVM and laryngeal mask airway (LMA) ventilation during CPR with continuous chest compressions. Methods: Emergency medicine residents and interns were included in the study. The participants were randomly assigned to resuscitation teams with two rescuers. The cross-over simulation study was conducted on two CPR scenarios: asynchronous ventilation via BVM during a continuous chest compression and asynchronous ventilation via LMA during a continuous chest compression in cardiac arrest patient with asystole. The primary endpoints were the ventilation-related measurements. Results: A total of 92 volunteers were included in the study and 46 CPRs were performed in each group. The mean rate of ventilations of the LMA group was significantly higher than that of the BVM group (13.7 [11.7-15.7] versus 8.9 [7.5-10.3] breaths/minute; P <.001). The mean volume of ventilations of the LMA group was significantly higher than that of the BVM group (358.4 [342.3-374.4] ml versus 321.5 [303.9-339.0] ml; P = .002). The mean minute ventilation volume of the LMA group was significantly higher than that of the BVM group (4.88 [4.15-5.61] versus 2.99 [2.41-3.57] L/minute; P <.001). Ventilations exceeding the maximum volume limit occurred in two (4.3%) CPRs in the BVM group and in 11 (23.9%) CPRs in the LMA group (P = .008). Conclusion: The results of this study show that asynchronous BVM ventilation with continuous chest compressions is a reliable and effective strategy during CPR under simulation conditions. The clinical impact of these findings in actual cardiac arrest patients should be evaluated with further studies at real-life scenes.

A landslide granular phase transition

Landslides appear in many different forms and sizes, from devastating debris flows to overly optimistic sand castles. A familiar and well-documented feature of all landslides is the positive correlation between volume and landslide runout. Larger landslides have a greater potential to reach farther. Here we explore the low volume limit and find a surprising negative correlation between volume and landslide runout. A decrease in volume leads to an increase in runout. In a series of experiments we systematically vary the landslide volume to reveal a transition between these two regimes.