Multi-facet classification of e-mails in a helpdesk scenario

Helpdesks have to manage a huge amount of support requests which are usually submitted via e-mail. In order to be assigned to experts e ciently, incoming e-mails have to be classi- ed w. r. t. several facets, in particular topic, support type and priority. It is desirable to perform these classi cations automatically. We report on experiments using Support Vector Machines and k-Nearest-Neighbours, respectively, for the given multi-facet classi - cation task. The challenge is to de ne suitable features for each facet. Our results suggest that improvements can be gained for all facets, and they also reveal which features are promising for a particular facet

A Captured Runaway Black Hole in NGC 1277?

Recent results indicate that the compact lenticular galaxy NGC 1277 in the Perseus Cluster contains a black hole of approximately 10 billion solar masses. This far exceeds the expected mass of the central black hole in a galaxy of the modest dimensions of NGC 1277. We suggest that this giant black hole was ejected from the nearby giant galaxy NGC 1275 and subsequently captured by NGC 1277. The ejection was the result of gravitational radiation recoil when two large black holes merged following the merger of two giant ellipticals that helped to form NGC 1275. The black hole wandered in the cluster core until it was captured in a close encounter with NGC 1277. The migration of black holes in clusters may be a common occurrence.Comment: Four pages, accepted by The Astrophysical Journal Letters. Major revisions, especially Section

Disk-Jet Connection in Agns and Microquasars: The Possibility of Thermal Flares in the Center

We discuss the possibility of thermal flares in centers of AGNs and microquasars. We present preliminary results of an ongoing study trying to assess the feasibility of a hypothesis suggesting that certain flares observed in these sources originate in the very centers of the systems and not in the relativistic jets. Using a simple toy model we reproduce optical flares with lightcurves very similar to those observed in the sources. The model suits especially well those cases where only the latter peak of a double-peaked optical flare has a radio counterpart.Comment: 6 pages, 1 figure, to appear in the proceedings of the HEPRO II conference, Buenos Aires, October 26-30 200

The Black Hole Mass - Galaxy Luminosity Relationship for Sloan Digital Sky Survey Quasars

We investigate the relationship between the mass of the central supermassive black hole, M_bh, and the host galaxy luminosity, L_gal, in a sample of quasars from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7). We use composite quasar spectra binned by black hole mass and redshift to assess galaxy features that would otherwise be overwhelmed by noise in individual spectra. The black hole mass is calculated using the photoionization method, and the host galaxy luminosity is inferred from the depth of the Ca II H + K features in the composite spectra. We evaluate the evolution in the M_bh - L_gal relationship by examining the redshift dependence of Delta log M_bh, the offset in black hole mass from the local black hole - bulge relationship. There is little systematic trend in Delta log M_bh out to z = 0.8. Using the width of the [O III] emission line as a proxy for the stellar velocity dispersion, sigma_*, we find agreement of our derived host luminosities with the locally-observed Faber-Jackson relation. This supports the utility of the width of the [O III] line as a proxy for sigma_* in statistical studies.Comment: 10 pages, 5 figures; final version; major revision

DiPel-Selected Ostrinia nubilalis Larvae Are Not Resistant to Transgenic Corn Expressing Bacillus thuringiensis Cry1Ab

The survival of KS-SC DiPel-resistant and -susceptible European corn borer, Ostrinia nubilalis (Hübner), was evaluated on different tissues from corn, Zea mays L., hybrids, including a nontransgenic and two transgenic corn plants (events MON810 and Bt11) expressing high doses of Bacillus thuringiensis (Bt) Cry1Ab. The survival of Bt-resistant and -susceptible third instars was similar after a 5-d exposure to transgenic plant tissues. Survivors eventually died when returned to Bt corn tissues, but many were able to continue development when transferred to non-Bt corn tissues. Survival of resistant and susceptible larvae also was evaluated in bioassays with dilutions of leaf extracts from the three corn hybrids incorporated in an artificial diet. In these assays, survival was significantly higher for resistant O. nubilalis neonates at three of the five dilutions compared with the susceptible strain, but the resistance ratio was only 2.2- and 2.4-fold for MON810 and Bt11, respectively. The data demonstrate that Bt-resistant and unselected control O. nubilalis larvae were similar in susceptibility to MON810 and Bt11 event corn hybrids. Although we were unable to evaluate the Cry1Ab protein that larvae were exposed to in the transgenic tissue because of company restrictions, Cry1Ab protoxin produced in Escherichia coli was incubated with extracts from non-Bt corn leaves to simulate the in planta effect on the transgenic protein. Cry1Ab protoxin was hydrolyzed rapidly by enzymes in the corn extract into peptide fragments with molecular masses ranging from 132 to 74 kDa, and eventually 58 kDa. Overall, these data suggest that plant enzymes hydrolyze transgenic toxin to one that is functionally activated. Therefore, resistant insect populations with reduced proteinase activity do not seem to pose a threat to the efficacy of commercial MON810 and Bt11 corn hybrids

Accretion Disk Temperatures of QSOs: Constraints from the Emission Lines

QSO emission-line spectra are compared to predictions based on theoretical ionizing continua of accretion disks. Observed line intensities do not show the expected trend of higher ionization with higher accretion disk temperature as derived from the black hole mass and accretion rate. This suggests that, at least for accretion rates close to the Eddington limit, the inner disk does not reach temperatures as high as expected from standard disk theory. Modified radial temperature profiles, taking account of winds or advection in the inner disk, achieve better agreement with observation. This conclusion agrees with an earlier study of QSO continuum colors as a function of disk temperature. The emission lines of radio-detected and radio-undetected sources show different trends as a function of disk temperature.Comment: 9 pages, 8 figures, submitted to Ap