Spectroscopic observations of comet Kohoutek (1973f), 2

Spectroscopic observations of comet Kohoutek at the Asiago Astrophysical Observatory are described. Spectra cover six nights before perihelion and five nights after perihelion. The spectra of the coma and tail of comet Kohoutek are characterized by fairly strong, asymmetric H2O(+) emissions in the red and the near infrared spectral regions and by the appearance of the 01 forbidden lines at 6300-6364 A, already at heliocentric distance r=1.55 A.U. These peculiarities suggest that some differences in chemical abundances or in physical conditions exist between comet Kohoutek and other comets

Pumping characteristics of the St707 non-evaporable getter (Zr 70-V 24.6-Fe 5.4 wt%)

The room temperature pumping speeds of the St707 Non-Evaporable Getter (NEG) have been measured both for individual gases and for gas mixtures as a function of the quantities of gas pumped. The interesting feature of this NEG consists in its moderately low activation temperature. Therefore particular attention has been devoted to defining the optimum temperature and duration of the activation process to obtain the highest possible pumping speed in a given practical situation. It has been found that heating at 400° C for about one hour or at 350° C for one day, results in pumping speeds of about 1000 ls-1m-1 for H2 , 2000 ls-1m-1 for CO and 450 ls-1m-1 for N2, values very close to those obtained after activation at the higher temperature of 740° C. The St707 NEG is therefore particularly suitable for passive activation during bakeout of stainless steel vacuum systems, avoiding the need of electrical insulation and feedthroughs which are mandatory when activation is carried out by resistive heating

A brittle fracture criterion for PMMA V-notches tensile specimens based on a length-enriched eXtended Finite Element approach

A criterion for the prediction of the static failure loads in tensile PMMA specimens with sharp notches is presented. The proposed criterion is based on a regularized version of the eXtended Finite Element Method (XFEM), which has been previously applied to concrete-like materials. The main feature of the proposed approach is that the cracking process is not treated as a local process, but it is modeled by assuming that macro-cracks stem from the interaction of micro-cracks within a finite width process zone. The case of a brittle materials with thin process zone is tackled by assuming one layer of enriched finite elements. Preliminary results concerning PMMA specimens subjected to mode-one loading are presented

The peculiar behaviour of the 5780 and 5797 DIBs in HD25137

The interstellar environment close to the high latitude molecular cloud Lynds 1569 (L1569, Lynds 1962), also known as MBM 18 (Magnani, Blitz and Mundy, 1985), has been analyzed by Penrase et al. (1990) and Penrase (1993). Their observations of the CH, CH(sup+), and CN molecular features, are consistent with a region having a high molecular and reduced dust content. They also observed the background star HD 24263- located 8 degrees far from the center of L1569 - reporting a CH rich line of sight and the presence of two intervening clouds from a sodium lines spectra. The infrared excess which has been revealed by the IRAS survey at 12 microns might suggest the presence of PAH's molecules, the well know candidate for the Unidentified Infrared Bands and Diffuse Interstellar Bands. This interesting scenario led to the investigation of the behavior of the diffuse interstellar bands toward HD 25137, which is supposed to be a background object for L1569 (Penrase et al., 1990); as well as the field star HD 24263. As part of a wider observational program devoted to study the HLC's special environments, the observations of the diffuse interstellar bands (DIB's) at 5780 and 5797 lambda lambda in the direction of the two above mentioned stars, HD 24263 and HD 25137 are presented here

Properties of some conformal field theories with M-theory duals

By studying classes of supersymmetric solutions of D=11 supergravity with AdS_5 factors, we determine some properties of the dual four-dimensional N=1 superconformal field theories. For some explicit solutions we calculate the central charges and also the conformal dimensions of certain chiral primary operators arising from wrapped membranes. For the most general class of solutions we show that there is a consistent Kaluza-Klein truncation to minimal D=5 gauged supergravity. This latter result allows us to study some aspects of the dual strongly coupled thermal plasma with a non-zero R-charge chemical potential and, in particular, we show that the ratio of the shear viscosity to the entropy density has the universal value of 1/4 pi.Comment: Consistent truncation extended to include fermions. Reference added. 28 page

Protein kinase CK2 is widely expressed in follicular, Burkitt and diffuse large B-cell lymphomas and propels malignant B-cell growth.

Serine-threonine kinase CK2 is highly expressed and pivotal for survival and proliferation in multiple myeloma, chronic lymphocytic leukemia and mantle cell lymphoma. Here, we investigated the expression of \u3b1 catalytic and \u3b2 regulatory CK2 subunits by immunohistochemistry in 57 follicular (FL), 18 Burkitt (BL), 52 diffuse large B-cell (DLBCL) non-Hodgkin lymphomas (NHL) and in normal reactive follicles. In silico evaluation of available Gene Expression Profile (GEP) data sets from patients and Western blot (WB) analysis in NHL cell-lines were also performed. Moreover, the novel, clinical-grade, ATP-competitive CK2-inhibitor CX-4945 (Silmitasertib) was assayed on lymphoma cells. CK2 was detected in 98.4% of cases with a trend towards a stronger CK2\u3b1 immunostain in BL compared to FL and DLBCL. No significant differences were observed between Germinal Center B (GCB) and non-GCB DLBCL types. GEP data and WB confirmed elevated CK2 mRNA and protein levels as well as active phosphorylation of specific targets in NHL cells. CX-4945 caused a dose-dependent growth-arresting effect on GCB, non-GCB DLBCL and BL cell-lines and it efficiently shut off phosphorylation of NF-\u3baB RelA and CDC37 on CK2 target sites. Thus, CK2 is highly expressed and could represent a suitable therapeutic target in BL, FL and DLBCL NHL

Baryonic Generating Functions

We show how it is possible to use the plethystic program in order to compute baryonic generating functions that count BPS operators in the chiral ring of quiver gauge theories living on the world volume of D branes probing a non compact CY manifold. Special attention is given to the conifold theory and the orbifold C^2/Z_2 times C, where exact expressions for generating functions are given in detail. This paper solves a long standing problem for the combinatorics of quiver gauge theories with baryonic moduli spaces. It opens the way to a statistical analysis of quiver theories on baryonic branches. Surprisingly, the baryonic charge turns out to be the quantized Kahler modulus of the geometry.Comment: 44 pages, 7 figures; fonts change

Structure Functions in Deep Inelastic Lepton-Nucleon Scattering

Latest results on structure functions, as available at the Lepton-Photon Symposium 1999, are presented. This report focusses on three experimental areas: new structure function measurements, in particular from HERA at low x and high Q2; results on light and heavy flavour densities; determinations of the gluon distribution and of alpha_s. As the talk was delivered at a historic moment and place, a few remarks were added recalling the exciting past and looking into the promising future of deep inelastic scattering.Comment: 27 pages, latex, 15 figures, Talk at Lepton-Photon Symposium, Stanford, August 199