Planar Rayleigh scattering results in helium-air mixing experiments in a Mach-6 wind tunnel

Planar Rayleigh scattering measurements with an argon—fluoride excimer laser are performed to investigate helium mixing into air at supersonic speeds. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment is demonstrated in a large-scale, Mach-6 facility. The detection limit obtained with the present setup indicates that planar, quantitative measurements of density can be made over a large cross-sectional area (5 cm × 10 cm) of the flow field in the absence of clusters

Charge carrier interaction with a purely electronic collective mode: Plasmarons and the infrared response of elemental bismuth

We present a detailed optical study of single crystal bismuth using infrared reflectivity and ellipsometry. Colossal changes in the plasmon frequency are observed as a function of temperature due to charge transfer between hole and electron Fermi pockets. In the optical conductivity, an anomalous temperature dependent mid-infrared absorption feature is observed. An extended Drude model analysis reveals that it can be connected to a sharp upturn in the scattering rate, the frequency of which exactly tracks the temperature dependent plasmon frequency. We interpret this absorption and increased scattering as the first direct optical evidence for a charge carrier interaction with a collective mode of purely electronic origin; here electron-plasmon scattering. The observation of a \emph{plasmaron} as such is made possible only by the unique coincidence of various energy scales and exceptional properties of semi-metal bismuth.Comment: 4 pages, 4 figure

A Semi-Empirical Model for Predicting the Frequency of Profile Vortex Shedding Relevant to Low-Speed Axial Fan Blade Sections

This paper extends existing semi-empirical models on the frequency prediction of vortex shedding. Moderate Reynolds numbers are investigated being of interest in low-speed axial fan design. By an extensive literature review, a new parametrization is proposed for the factor establishing a connection between boundary layer properties and vortex shedding characteristics. Measurement data on symmetrical and non-symmetrical NACA profiles, and on flat and cambered plates, are processed. It is found that the value of the factor is influenced by the relative thickness of the profiles and by the angle of attack. Based on the measurement results, an empirical value is given for the vortex spacing ratio for flow past airfoils. With the use of the proposed empirical model, the vortex shedding frequency of various airfoil profiles and operating conditions can be predicted

Estimates of higher-dimensional vacuum condensates from the instanton vacuum

We calculate the values of non-factorizable dimension-7 vacuum condensates in the instanton vacuum. We comment on a method, recently proposed by Oganesian, to estimate the dimension-7 condensates by factorization of dimension-10 condensates in various inequivalent ways. The instanton estimates could be used to analyze the stability of QCD sum rules with increasing dimensions.Comment: 8 pages, Late

A Possible Role of Elevated Breast Milk Lactoferrin and the Cytokine IL-17 Levels in Predicting Early Allergy in Infants: A Pilot Study

In this study, we examined the relationship between levels of lactoferrin (LF) and IL-17 in human serum and breast milk and the development of allergy in children. LF and IL-17 levels were determined by ELISA in healthy (n=19) and allergic mothers (n=21) on the 5th day after delivery. Two years later, information on breastfeeding and allergic outcomes was collected by questionnaires from parents of both groups and district child care nurses. Significantly higher concentrations of LF were found in the breast milk of allergic mothers compared to the healthy controls. At 2 years of age, only those three infants became allergic from the atopic group in whose starting breast milk samples a very high LF level (306 μg mg–1 protein) or simultaneously elevated concentrations of LF and IL-17 were measured. These findings indicate that the very early measurement of LF and IL-17 levels in the breast milk of allergic mothers may help to predict the allergy development in their infants

Nationwide analysis of open groin hernia repairs in Italy from 2015 to 2020

Introduction: Inguinal hernia repair is one of the most commonly performed operations in general surgery. A total of 130.000 inguinal hernia repairs are performed yearly in Italy, and approximately 20 million inguinal hernias are treated worldwide annually. This report represents the trend analysis in inguinal hernia repair in Italy from a nationwide dataset for the 6-year period from 2015 to 2020. Materials and methods: Based on regional hospital discharge records, all the inguinal hernia repairs performed in public and private hospitals in Italy between 2015 and 2020 were reviewed based on diagnosis and procedure codes. For the aim of this study, data from the AgeNas (The National Agency for Regional Health Services) data source were analyzed. Results: Elective inguinal hernia repairs outnumbered urgent operations over the 6-year study period, ranging from 122,737 operations in 2015 to 65,780 in 2020 as absolute numbers, and from 87.96 to 83.3% of total procedures in 2019 and 2020 respectively, with an annual change ranging from - 66.58%, between 2020 and 2019, to - 2.49%, between 2019 and 2018 (mean = - 18.74%; CI =- 46.7%-9.22%; p < 0.0001). Conclusions: This large-scale review of groin hernia data from a nationwide Italian dataset provides a unique opportunity to obtain a snapshot of open groin hernia repair activity. More specifically, there is a trend to perform more elective than urgent procedures and there is a steady decrease in the amount of open hernia repairs in favor to laparoscopy

L'ontologie du pouvoir politique postcolonial au Cameroun unanisme dialectique et divorce métaphysique (critique philosophique de l'histoire d'une monocratie

Ordonnée autour d'une seule et même entité thématique : celle d'élucider« l'ontologie du pouvoir politique», cette thèse est principalement axée sur une critique radicale de l'histoire politique du Cameroun. Critique constituée en un ensemble tripartite, qui se développe de la manière suivante : premièrement, un exposé de quelques jalons et présupposés philosophiques; il comprend trois chapitres : les repères ontologiques et anthropologiques, puis l'être vrai du pouvoir politique. Deuxièmement, une phénoménologie temporelle du pouvoir politique postcolonial élucidée par ses manifestations caractéristiques et étayée d'un bout à l'autre par un support visuel judicieux. On doit y noter deux volets principaux : la parturition du Cameroun : genèse du concept nominatif du «Kamerun», naissance et description du Cameroun en tant que tel; et la recherche phénoménologique du sens de l'État du Cameroun. Cette partie vise surtout à révéler ce qu'est l'ontologie de ce pouvoir. Troisièmement, enfin, l'ordre critique aux niveaux collectif et individuel. Il comprend, entre autres, l'élaboration d'une critique de l'essence et celle du fondement du pouvoir politique postcolonial. Une approche qui vise à ouvrir des perspectives politiques susceptibles d'améliorer la réalité existentielle du peuple camerounais