We report on Monte-Carlo calculations of the emergence of X- and γ-rays from the envelope of the supernova 1987A. Assuming that there exists an X-ray emitting pulsar at the centre, we discuss the possibilities of observing its radiation and find that if the pulsar is about as luminous as the present-day Crab, it may be possible to detect the breakout at ~ 20 months. The pulsar should emerge first in the 6-16 keV band covered by GINGA. About six months later it would appear in the 20-45 keV band of MIR-HEXE. Because the optical depth of the envelope at breakout is still substantial (~4), we do not expect pulses to be detected straightaway. Our conclusions are based on a simple homogeneous model for the envelope and do not depend on whether or not ^56^Co is mixed into the outer layers. The time at which a pulsar of higher luminosity would emerge can be obtained from a simple scaling of our results.
Στο μονόπρακτο του Άρθουρ Σνίτσλερ Ο πράσινος παπαγάλος [DergrüneKakadu] κυριαρχεί ο προβληματισμός γύρω από την ουσία της πραγματικότητας. Γάλλοι αριστοκράτες επισκέπτονται την παραμονή της Γαλλικής Επανάστασης ένα ιδιόρρυθμο θέατρο-καπηλειό του Παρισιού, όπου οι θαμώνες είναι ηθοποιοί που παριστάνουν κακοποιούς και απατεώνες. Η ευχάριστη διέγερση των νεύρων που προσφέρουν στους αριστοκράτες οι επινοημένες αφηγήσεις των ηθοποιών έρχεται σε αντίθεση με αυτό που πραγματικά συμβαίνει και που οι αριστοκράτες αποφεύγουν να συνειδητοποιήσουν: τη στιγμή που εκείνοι απολαμβάνουν την ψευδαίσθηση της απειλής και του κινδύνου, ξεσπάει έξω, στους δρόμους του Παρισιού, η Επανάσταση. Το βασικό θέμα του έργου είναι αντιπροσωπευτικό της εποχής που γράφτηκε, δηλαδή του Fin-de-siècle, της Βιεννέζικης Νεωτερικότητας αφού ο Σνίτσλερ εστιάζει στα παρακμιακά στοιχεία και στο θέμα της αποσύνθεσης της πραγματικότητας. Ακόμα και ο χαρακτηρισμός «γκροτέσκο» που χρησιμοποιεί ο συγγραφέας για το έργο δεν δικαιολογείται με αυστηρά λογοτεχνικά κριτήρια, αλλά σκοπό έχει να τονίσει την ιδιομορφία των συμβάντων στον Παπαγάλο και να σχολιάσει τη στάση του κοινού που τα υπαγορεύει και τα προκαλεί.Arthur Schnitzlers Einakter "Der grüne Kakadu" (1898), vom Autor als Groteske bezeichnet, variiert das bei Schnitzler beliebte Thema des Verhältnisses zwischen Illusion und Realität. Im historischen Kostüm gekleidet - Französiche Aristokraten geben sich am Vorabend der Revolution in einer kabarettartigen Spelunke dem Spiel mit der Illusion hin, ohne die nahende Katastrophe wahrzunehmen - lassen sich die Figuren des Stücks nach dem Grad ihres Wirklichkeitsverhältnisses charakterisieren. Schon die Wahl des historischen Moments impliziert eine kritische Haltung gegenüber einer realitätsabblendenden Attitüde, die letztendlich auf Schitzlers Zeit und Gesellschaft hinweist.
Self-consistent, first-principles calculations are presented for the electronic structure of some point defects in the binary alloys CoAl and CoGa. All possible structural defects-i.e., antistructure atoms and vacancies-as well as 3d transition-metal impurities on both sublattices are considered. The calculations are based on the Korringa-Kohn-Rostoker Green's-function method and on density-functional theory in the local-spin-density approximation. The calculated densities of states, charge transfers, and magnetic moments are discussed and compared with the results of other theoretical calculations and the available experimental data.
We report about self-consistent calculations for dilute Ni alloys, which are based on density-functional theory and the Korringa-Kohn-Rostoker Green's-function method. In particular, we calculate the charge and magnetization perturbations for four shells of atoms around the impurity. Impurities of the 3d, 4d, and 4sp series are considered. Of central interest is the transition from strong to weak ferromagnetism and the different screening mechanism in these alloys. We compare our results for the perturbations of the local moments as well as the change of the total moment with magnetization and neutron scattering data.
A detailed model for positron production by a young pulsar is presented. It is shown that electromagnetic cascades can develop in a young pulsar's magnetosphere, and the model results are applied to the pulsar which is hypothesized to lie near the Galactic center. It is found that such a pulsar would be expected to produce relatively low energy electron-positron pairs with an efficiency rating high enough to explain the observed luminosity of the Galactic center annihilation line. Virtually all of the gamma ray continuum radiation produced in the cascades would be beamed along the magnetic poles of the neutron star, and therefore probably would not be observed from earth. Some observational predictions generated by the proposed model for the Galactic center positron source are given.
We consider the electronic structure of dilute Pd and discuss reasons for the disagreement between experiment and theory, especially concerning the Pd density of states. The intensity of the low energy Pd peak, obtained in previous calculations, is very sensitive to charge transfer, lattice relaxation and relativistic effects. Realistic ab-initio calculations, which take these effects properly into account, practically remove the intensity of the low energy Pd peak and are in much better agreement with experiments than previous single site and KKR-CPA results.
High-energy (70 MeV < E < 5 GeV) gamma-ray observations of Cyg X-3 by the ESA satellite COS-B and hard X-ray (14 keV < E < 140 keV) observations by the Leiden-MIT balloon experiment, Leimit, are presented. A comparison with, and a study of earlier results over the 14 decades in energy from 1 keV up to ≡1017eV indicates that the strong variability of Cyg X-3 over more than one order of magnitude at energies below 20 keV does not exhibit itself in the data collected at hard X-ray energies, and the power emitted per decade of energy reaches a minimum in the MeV-GeV region. If the primary gamma-rays up to 1015eV originate close to the central source, absorption by the keV X-rays in the Cyg X-3 binary system could explain the latter phenomenon.
An investigation of the star clusters in the outermost areas of the LMC has started in order to examine the observed dynamical properties of the halo globular clusters in this galaxy. A first sample of 38 clusters have been measured by means of star counts on plates taken with the 1.2 m U.K. Schmidt telescope. The derived tidal radii and masses are comparable to those found for the disk young clusters of the LMC and those of the galactic globulars.
We develop a formalism to take into account the lattice relaxation around an impurity within the Korringa-Kohn-Rostoker Green's-function method. Using this formalism and the density-functional theory in the local spin-density approximation we perform first-principles, self-consistent calculations for the electronic structure of some dilute metallic alloys. In particular, we investigate the influence of lattice relaxations on the local magnetic moments in CuMn, CuFe, CuCo, and NiMn.
We report on self-consistent ab-initio calculations for the electronic structure of intrinsic defects in CoAl, i.e. antistructure (AS) Co atoms and vacancies on the Co sublattice. The calculations are based on the Korringa-Kohn-Rostoker (KKR) Green's function method and employ the local spin density approximation of the density functional theory. The results for the densities of states, the charge transfers and the local moments are discussed and compared with the available experimental data.
The electronic structure of a simple model for (La, Ce, Th, U)Be13 compounds is determined self-consistently within the density functional theory. The rare earth or actinide atom is considered as a spherically symmetric impurity embedded in a jellium. The width and position of f-localised states result naturally from the scattering of conduction electrons by the impurity potential. The results of the author's calculation for electronic specific heat, position and width of f-resonant states are compared with available theoretical results and experimental data.
The fully differential cross section for photon-electron pair production is integrated numerically over phase space. Results are obtained for the astrophysically interesting case in which the interaction between an ultrarelativistic electron and a soft photon results in electron-positron pair production. The positron spectrum is a function of the energies of both the photon and the electron, as well as the angle of interaction. It is found that the energy at which the positron distribution peaks is inversely proportional to the photon energy and independent of the electron energy. The positron spectrum is integrated once more over initial electron energies for a power-law energy distribution of primary electrons. The same procedure is repeated for the recoil particle; it is shown that the peak of the recoil energy distribution depends linearly on the energy of the primary electron. Finally, semianalytical expressions are obtained for the energy losses of the primary electrons.
A mechanism for producing the high energy γ-ray spectrum of X-ray binaries exhibiting ultra-high-energy activity is proposed. γ-rays can result from decay of π0 produced in collisions of energetic protons with the keV ambient photons. Consequently, the X-ray photons modify the produced primary spectrum by selectively absorbing the lower energy part of it. As a result of this differential absorption these systems should exhibit a power law spectrum of index 1.5 - 2.0. Moreover, these systems should have a high electron-positron pair number density that will lead to 511 keV annihilation line emission.
The general formalism describing the electronic structure of dilute impurities in ordered compounds within the linear-muffin-tin-orbital approximation is presented. It is derived by considering the proper limit in the Green-function theory within the multiple-scattering formalism. The method thus obtained retains the advantages of the Green-function method for ab initio self-consistent calculations, but with reduced numerical efforts. We discuss in great detail several important aspects of its practical application towards point defects in cubic ordered metallic compounds; the part played by Friedel's screening rule, the calculation of the charge perturbations induced in the host, and the use of the complex-plane integration method are especially stressed.
Ab initio self-consistent electronic-structure calculations of vacancies in ordered stoichiometric FeAl within the linear-muffin-tin-orbital atomic-sphere-approximation method are presented. The potential and local densities of states on the defect and the charge perturbations on its neighboring sites in the matrix are calculated and discussed in relation with numerous experimental results concerning the effect of small departures from stoichiometry for this ordered compound.
A case of a patient presenting with the symptoms of lifelong xerostomia is discussed. Clinical investigation demonstrated aplasia of all the major salivary glands, lacrimal gland hypoplasia and enamel hypoplasia. The management and aetiology of the case is discussed.
Στα πλαίσια του αφιερώματος του λογοτεχνικού περιοδικού «Διαβάζω» στον Γιόχαν Βόλφγκαγκ φον Γκαίτε γίνεται με το άρθρο αυτό αναφορά στη σχέση του Γκαίτε με την αρχαία ελληνική λογοτεχνία και σύγκριση της «Ιφιγένειας εν Ταύροις» του Γκαίτε με το έργο του Ευριπίδη. Παρουσιάζεται η εξιδανικευμένη άποψη του κλασικισμού για την ελληνική αρχαιότητα και σχολιάζεται η αναθεώρηση της άποψης αυτής στον ύστερο κλασικισμό.
Barbaresi F, Lunghini С BС, Canevá M, Cotogni A, Musacci GF, Rigatelli G, Volta G, Beckers J, Vandeputte R, Geoers J, et al.Hypertrophic cardiomyopathy. Int J Cardiol. 1985;7:159–160.
Ab initio self-consistent calculations are presented of the electronic structure of sp and 3d impurities in simple and ferromagnetic alloys. The calculations have been performed according to the LMTO-ASA method, fully taking into account the band structure of the host.The density functional theory has been used in the local spin-density approximation; the impurity potential is assumed to be of the muffin-tin form and lattice relaxation effects are neglected. Friedel's sum rule is always satisfied during the calculation. Charge and spin-density perturbation induced in the matrix are computed up to the fourth-nearest neighbour shell.The present theoretical results obtained for local moment, hyperfine field on the impurity, change in the saturation magnetization and magnetic perturbation effects induced by the impurity on the neighbouring atoms are in good agreement with the available experimental data.
The distribution of phenotypes and gene frequencies of the third component of complement (C3), group-specific component (Gc), haptoglobin (Hp) and transferrin (Tf) were studied in 115 patients with carcinoma of the prostate. The statistical analysis of our findings in comparison to the frequency of these genes in a control group of 155 patients with benign prostatic hyperplasia does not reveal any correlation between the distribution of the Hp and Tf phenotypes and the disease. On the contrary, a statistically significant association was found between carcinoma of prostate and C3(F) and Gc2 genes. The relative risk incidence of this malignancy is 1.56 and 1.81, respectively, for the carriers of these genes suffering from benign prostate hyperplasia.
The distribution of phenotypes and gene frequencies of the 3rd component of complement (C3), group-specific component (G(c)), haptoglobin (Hp) and transferrin (T(f)) were studied in 50 patients with renal adenocarcinoma. The statistical analysis of our findings in comparison to the frequency of these genes in the general population does not reveal any correlation between the distribution of the Hp and Tf phenotypes and the disease. On the contrary, a statistically significant association was found between renal adenocarcinoma and C3(F) and Gc 2 genes. The relative risk incidence of this malignancy is 2.07 and 1.94 respectively for the carriers of these genes. These data indicate that genetic factors, possibly related to the immune mechanisms and calcium metabolism, play a role in the pathogenesis of renal adenocarcinoma.
La région thessalienne, dans cette étude, devient la matière première d’une expérience: celle de la création d’une méthodologie en ce qui concerne l’analyse géographique de réseaux de transports (terrestres et maritimes) des marchandises sous un angle qualitatif et quantitatif. La superficie de la région occupée le 1/10e de la superficie totale de la Grèce, dont le secteur primaire occupe 40% de son activité économique; ceci nous fait comprendre l’importance de la participation de la région thessalienne à la formation du P.N.B. du pays. Il faut bien souligner aussi que le caractère géomorphologique et climatique de cette région crée une différenciation économique très frappante entre la partie occidentale et la partie orientale de la région. La partie orientale, une plaine vaste et fertile, se trouve au milieu de la Grèce, site privilégie qui doit ses avantages à l’existence de l’axe principal routier et ferroviaire de la Grèce, qui relie Athènes à Salonique. La partie occidentale se caractérise au point de vue géomorphologique par les grands massifs montagneux qui sont essentiellement les causes de son sous-développement économique (avec toutes les conséquences socioculturelles qui l’accompagnent). Cette partie est éloignée des grands axes routiers et des accès maritimes (portuaires), fait qui intensifie l’attardement économique. La plupart des sous-régions administratives (éparchies) de cette partie, sont caractérisées dans cette étude ‘en difficulté’ et d’un caractère en majorité agricole (élevage, bois) sous-développée. Le manque d’infrastructure en matière de transports, et la mise en valeur de certaines liaisons routières et maritimes avec l’Europe du nord, dont la possibilité de création se présente dans cette étude, accompagne d’une incapacité au point de vue aménagement du territoire dont fait preuve le Ministère de la Coordination, nous ont poussé à l’effort de la création d’une méthodologie d’analyse qui sera capable de mettre en relief de façon qualitative et quantitative les caractéristiques et les paramètres des flux des transports de marchandises, flux qui se créent d’après les fonctions économico-sociales de l’espace géographique donne.
The distribution of phenotypes and gene frequencies of the C3 component of complement, group-specific component, transferrin and haptoglobin were studied in 155 patients with benign prostatic hyperplasia. A statistical analysis of the findings in comparison with the frequency of these genes in the general population failed to demonstrate any correlation between phenotype distribution and benign prostatic hyperplasia.
The distribution of the phenotypes and the gene frequency of the 3rd fraction of complement (C3), the specific group (Gc), haptoglobin (Hp) and transferrin were studied in 133 patients with transitional cell cancer of the bladder (papillary cancer). Statistical analysis of these results, in comparison with the frequency of these genes in the general population, was unable to demonstrate a correlation between the distribution of these phenotypes and papillary cancer.
We present the results of the calculation of the electronic structure of impurities (Ti, V, Cr, Mn, Co, Ni, Cu) diluted in ferromagnetic iron obtained by the method of linear combination of «muffin-tin» orbitals in the atomic sphere approximation (LMTO-ASA). The local moments and the hyperfine fields on the impurity and the electronic specific heat coefficient charges are compared with the experimental data.
Terzaki AK, Cokkinos DV, Leachman RD, Meade JB, Hallman GL, Cooley DA. Combined mitral and aortic valve disease. The American journal of cardiology. 1970;25:588–601.
