General Relativistic Magnetohydrodynamic Bondi--Hoyle Accretion

In this paper we present a fully relativistic study of axisymmetric magnetohydrodynamic Bondi--Hoyle accretion onto a moving Kerr black hole. The equations of general relativistic magnetohydrodynamics are solved using high resolution shock capturing methods. In this treatment we consider the ideal MHD limit. The parameters of interest in this study are the adiabatic constant $\Gamma$, the asymptotic speed of sound $c_{s}^{\infty}$, and the plasma beta parameter $\beta_{P}$. We focus the investigation on the parameter regime in which the flow is supersonic, or when $v_\infty \ge c_{s}^{\infty}$. In some cases, subsonic asymptotic flows are considered for comparison purposes. We study the accretion rates of the total energy and momenta, as well as the hydrodynamic energy and momentum accretion rates. The models presented in this study exhibit a matter density depletion in the downstream region of the black hole which tends to vacuum $(\rho_0=0)$ in convergence tests. This feature is due to the presence of the magnetic field, more specifically the magnetic pressure, and is not seen in previous purely hydrodynamic studies.Comment: Version 2: The figures have been reformatted to fit the paper. All verbal content remains identical to version

Modified gravity without dark matter

On an empirical level, the most successful alternative to dark matter in bound gravitational systems is the modified Newtonian dynamics, or MOND, proposed by Milgrom. Here I discuss the attempts to formulate MOND as a modification of General Relativity. I begin with a summary of the phenomenological successes of MOND and then discuss the various covariant theories that have been proposed as a basis for the idea. I show why these proposals have led inevitably to a multi-field theory. I describe in some detail TeVeS, the tensor-vector-scalar theory proposed by Bekenstein, and discuss its successes and shortcomings. This lecture is primarily pedagogical and directed to those with some, but not a deep, background in General RelativityComment: 28 pages, 10 figures, lecture given at Third Aegean Summer School, The Invisible Universe: Dark Matter and Dark Energy, minor errors corrected, references update

lmmunomorphologica characteristics of renal cell carcinoma

Immunomorphological characteristics of 27 renal cell carcinoma (RCC): 18 clear cell, 6 granular (chromophilic), 2 chromophobe, 1 spindle cell (sarcomatoid) as well as of 1 oncocytoma, were analyzed. The investigation was performed on cryostat sections by immunoperoxidase technique applying a panel of monoclonal antibodies which defined: proximal (TNE3, TN5, 5D9) and distal (TN8, TN9, 7C2) tubular antigens; intercellular adhesion molecule 1 (ICAMl); HLA class I1 (-DQ, -DR and -DP) antigens, intermediary filaments (cytokeratin and vimentin); and antigens on tumour infiltrating mononuclear leucocytes (TT1, TT2 and LeuM3 for CD4, CD8 and CD14 antigens, respectively). All RCC with exception of chromophobe CO-expressed cytokeratin and vimentin. In addition, they were usually positive for all proximal and two distal tubular markers (TN8, TN9) indicating primitive cells which could differentiate into the epithelium of both parts of tubule system as the most probable originators of in RCC. Almost all RCC but the chromophobe aberrantly expressed HLA class I1 antigens which great variability from case to caie. The presence of HLA-DR antigens was more intensive and widespread than of HLA-DQ and-DP antigens. Expression of ICAMl mostly correlated with presence of HLA class I1 antigens, particularly with -DR on tumour cells of RCC HLA-DR antigen expression was always more prominent than mononuclear cell infiltrate (among which macrophages prevailed over T cells) which could suggest that increased histocompatibility antigen expression precedes mononuclear cell influx. In contrast to all other RCC, chromophobe tumours had quite distinct features revealing the most intense reaction with 7C2 (MAb that produced the weakest reaction with other tumour types), absence of vimentin and very weak reaction with antibodies for HLA class Il Ag and ICAM 1. Since oncocytoma has similar immunohistological properties it could be supposed that both tumours have common histogenesis

Marine carbonate systems in the Sarmatian (Middle Miocene) of the Central Paratethys: the Zsámbék Basin of Hungary

The study of eight stratigraphic sections at the margin of the semi-enclosed Zsa´mbe´k Basin (Hungary) allows the sedimentary anatomy of oolitic–bioclastic systems in the Sarmatian of the Central Paratethys to be reconstructed. The mollusc, foraminiferal and ostracod associations indicate that the carbonate systems are Latest Badenian to Late Sarmatian in age. The Lower–Upper Sarmatian deposits are organized in superimposed subaqueous dunes prograding towards the basin on a low-angle ramp. During the Late Sarmatian, the ramp underwent subaerial erosion linked to a moderate relative fall in sea-level. Lagoonal deposits were later formed and microbial–nubeculariid–bryozoan–serpulid buildups were emplaced. The ‘abnormal’ marine conditions of the Sarmatian, conducive to the development of a poorly diversified flora and fauna and dominant non-skeletal grains, are linked to fluctuating salinities, mesotrophic to eutrophic conditions and perhaps high alkalinity