Analysis of the electron component of EAS at observational level 700 g x cm(-2) with a scale breaking interaction model and gammaisation hypothesis

Scale breaking model and gammaisation processes for high energies give a correct description of the longitudinal development of extensive air showers (E.A.S.). From the analysis of phenomenological characteristics of E.A.S. at Tien-Shan experiment, it follows that for energies near 10 to the 6 GeV the secondary particle multiplicity increases with energy faster than is predicted by the accepted scale breaking model

VERBAL CHOICE IN ISCHEMIC STROKE PATIENTS WITH ANOMIC APHASIA.

Background and purposes: Anomic aphasia is common in patients with left hemispheric strokes. The purpose of this study was to explore the verbal production of ischemic stroke patients with anomic aphasia. Contingent and methods: Fifty ischemic stroke patients admitted to the Neurology Clinic of University Hospital Pleven were studied by neuropsychological battery and CT scan of the brain. Verbal productivity changes found were analyzed in relation to the speech recovery education. Results: All the patients showed lower scores at all nominative and reproductive speech subtests. Discussion: Among the ischemic stroke patients with mild anomic aphasia comparatively great was the percentage of low frequency word actualization and verbal fluency impairment. The usage of nominatives in speech expression of ischemic stroke patients is less as compared with that one of predicatives. Actualization of particles, unions, prepositions and interjections was comparatively high thus compensating the difficulty in choice of a definite lexical number. Conclusion: Future studies on testing of verbal choice in ischemic stroke patients should confirm its practical significance for the assessment of speech disorders concerning a special speech- recovery education

Media Attention and Event-Based Grouping of Stocks: An Examination of Stocks Hyped by Media Outlets as Benefiting from the Olympics

We examine five summer Olympics and identify stocks that media outlets hype as benefiting from the Olympics (Olympic stocks). There is a seven-year period from the time that a country first learns it has won the Olympic bid to the start of the games (Olympic time period). We predict that the excitement of the Olympics along with the greater media attention impacts the valuation and risk of Olympic stocks. Consistent with this prediction, we show that Olympic stocks earn higher returns than their matched counterparts and comove more strongly with each other over the Olympic time period. Olympic stocks also exhibit increases in trading volume and stock volatility on days when media outlets have stories linking the firm to the Olympic Games. However, we find no evidence that the Olympic Games translate into stronger fundamentals for Olympic firms or stronger fundamental co-movements. These findings suggest that investors are not purchasing the stocks based on an analysis of fundamentals, but are purchasing them based on their Olympic attribute. To confirm that event-based groupings occur in other settings, we show that co-movement increases for stocks classified by the media as “stay-at-home” stocks at the start of the COVID-19 pandemic. This paper was accepted by Eric So, accounting. Supplemental Material: The online appendix is available at [https://doi.org/10.1287/mnsc.2021.02218](https://doi.org/10.1287/mnsc.2021.02218

Ferromagnetism in defect-ridden oxides and related materials

The existence of high-temperature ferromagnetism in thin films and nanoparticles of oxides containing small quantities of magnetic dopants remains controversial. Some regard these materials as dilute magnetic semiconductors, while others think they are ferromagnetic only because the magnetic dopants form secondary ferromagnetic impurity phases such as cobalt metal or magnetite. There are also reports in d0 systems and other defective oxides that contain no magnetic ions. Here, we investigate TiO2 (rutile) containing 1 - 5% of iron cations and find that the room-temperature ferromagnetism of films prepared by pulsed-laser deposition is not due to magnetic ordering of the iron. The films are neither dilute magnetic semiconductors nor hosts to an iron-based ferromagnetic impurity phase. A new model is developed for defect-related ferromagnetism which involves a spin-split defect band populated by charge transfer from a proximate charge reservoir in the present case a mixture Fe2+ and Fe3+ ions in the oxide lattice. The phase diagram for the model shows how inhomogeneous Stoner ferromagnetism depends on the total number of electrons Ntot, the Stoner exchange integral I and the defect bandwidth W; the band occupancy is governed by the d-d Coulomb interaction U. There are regions of ferromagnetic metal, half-metal and insulator as well as nonmagnetic metal and insulator. A characteristic feature of the high-temperature Stoner magnetism is an an anhysteretic magnetization curve which is practically temperature independent below room temperature. This is related to a wandering ferromagnetic axis which is determined by local dipole fields. The magnetization is limited by the defect concentration, not by the 3d doping. Only 1-2 % of the volume of the films is magnetically ordered.Comment: 22 pages, 6 figure

Sub-picosecond exchange-relaxation in the compensated ferrimagnet Mn2_2Rux_xGa

We study the demagnetization dynamics of the fully compensated half-metallic ferrimagnet Mn$_2$Ru$_x$Ga. While the two antiferromagnetically coupled sublattices are both composed of manganese, they exhibit different temperature dependencies due to their differing local environments. The sublattice magnetization dynamics triggered by femtosecond laser pulses are studied to reveal the roles played by the spin and intersublattice exchange. We find a two-step demagnetization process, similar to the well-established case of Gd(FeCo)$_3$, where the two Mn-sublattices have different demagnetization rates. The behaviour is analysed using a four-temperature model, assigning different temperatures to the two manganese spin baths. Even in this strongly exchange-coupled system, the two spin reservoirs have considerably different behaviour. The half-metallic nature and strong exchange coupling of Mn$_2$Ru$_x$Ga lead to spin angular momentum conservation at much shorter time scales than found for Gd(FeCo)$_3$ which suggests that low-power, sub-picosecond switching of the net moment of Mn$_2$Ru$_x$Ga is possible.Comment: 5 pages, 3 figures, J. Phys.: Condens. Matter (2021

Can the polarization of the strange quarks in the proton be positive ?

Recently, the HERMES Collaboration at DESY, using a leading order QCD analysis of their data on semi-inclusive deep inelastic production of charged hadrons, reported a marginally positive polarization for the strange quarks in the proton. We argue that a non-negative polarization is almost impossible.Comment: 6 pages, latex, minor changes in the discussion after Eq. (9