Shakhbazian compact galaxy groups. II. Photometric and spectroscopic study of ShCG 376

The results of the redshift measurements and of the detailed surface photometry in BVR of the compact group ShCG 376 are presented. The radial velocity dispersion, the virial mass, the total luminosity, the M/L ratio, and the crossing time of the group are estimated. The group consists of eight accordant redshift spiral galaxies. Four (or possibly five) of the group members have emission-line spectra. Such morphological content and the number of emission-line galaxies are very atypical for compact galaxy groups. There are signs of interaction between some members of the group. It is suggested that the irregular shape of the brightest galaxy No. 4 is probably due to interaction with other members of the group, particularly, the emission line galaxy No. 6 with a discordant redshift (Delta v = 2600 km/s). It is speculated that the latter galaxy may be a infalling intruder to the group.Comment: accepted A&A, 7 pages, 6 figures are in separate file

Non-Markovian decoherence in the adiabatic quantum search algorithm

We consider an adiabatic quantum algorithm (Grover's search routine) weakly coupled to a rather general environment, i.e., without using the Markov approximation. Markovian errors generally require high-energy excitations (of the reservoir) and tend to destroy the scalability of the adiabatic quantum algorithm. We find that, under appropriate conditions (such as low temperatures), the low-energy (i.e., non-Markovian) modes of the bath are most important. Hence the scalability of the adiabatic quantum algorithm depends on the infra-red behavior of the environment: a reasonably small coupling to the three-dimensional electromagnetic field does not destroy the scaling behavior, whereas phonons or localized degrees of freedom can be problematic. PACS: 03.67.Pp, 03.67.Lx, 03.67.-a, 03.65.Yz

Lokale Clanchefs im römischen Nordafrika

Im Zentrum der Untersuchung stehen Clanchefs und ihre Rolle bei der Integration von Nomadenstämmen unter römische Verwaltung in den Jahren der römischen Herrschat über Nordafrika von 146 v. Chr. bis ins 5. Jh. n. Chr. Ausgangspunkt der Überlegungen war, daß die ausschließlich in Personenverbänden verlaufende Organisation nomadischer Stämme für die nach dem Kriterium der Ortsfestigkeit operierende römische Verwaltung nach der Eroberung Nordafrikas 146 v. Chr. eine neuartige Herausforderung darstellte. Und es waren v. a. die Anführer dieser Stämme, deren lokale Autonomieansprüche durch die gegenüber den vorherigen Numiderkönigen intensivere Kontrolltätigkeit der Römer eingeschränkt wurden und die deshalb verstärkt rebellierten. Deshalb wurde untersucht, wie der römischen Verwaltung eine Adaption an diese andersartigen lokalen Machtstrukturen gelang. In der Tat ist die zunehmende Stabilität der römischen Herrschat ab dem 2. Jh. n. Chr. nicht unwesentlich mit der erfolgreichen Einbindung nomadischer Clanchefs verknüpt, die z. B. durch Bürgerrechtsverleihungen privilegiert wurden, während das Machtgefüge innerhalb der Stämme und damit lokale Machtstrukturen weitgehend unangetastet blieben. Dies führte zu der ambivalenten Situation, daß der schwindende Einfluss Roms in Nordafrika ab dem 5. Jh. zwar in ein erneutes Erstarken der Territorialmacht von Nomadenstämmen mündete, deren Anführer sich aber weiterhin auf Rom als Quelle ihres Prestiges beriefen.The study focusses on tribal chiefs and their role in integrating nomadic tribes into the Roman administration between 146 BC and the 5th century AD when Rome ruled over North Africa. It acted on the assumption that the specific organizational structure of nomadic tribes, based primarily on personal loyalties, represented a novel challenge for the Roman administration, which was based on a sedentary structure of its subjects. Similarly, the Roman administration posed a threat to the nomadic chietains as well, because it manifested an intensified form of control in comparison with the Numidian kings who had previously ruled large parts of North Africa. Therefore, it was predominantly these chietains who initially led the fierce resistance against Rome. The study raised the question how the Roma

The Properties of the Heterogeneous Shakhbazyan Groups of Galaxies in the SDSS

We present a systematic study of the sub-sample of Shakhbazyan groups (SHKs) covered by the Sloan Digital Sky Survey Data Release--5 (SDSS-5). SHKs probe an environment with characteristics which are intermediate between those of loose and very compact groups. Surprisingly, we found that several groups identifying algorithms (e.g. Berlind et al. 2006, Tago et al. 2008) miss this type of structures. Using the SDSS-5 spectroscopic data and the photometric redshifts derived in D'Abrusco et al. 2007, we identified possible group members in photometric redshift space and derived, for each group, several individual properties. We also combined pointed and stacked Rosat All Sky Survey data to investigate the X-ray luminosities of these systems. Our study confirms that the majority of groups are physical entities with richness in the range 3--13 galaxies, and properties ranging between those of loose and compact groups. We confirm that SHK groups are richer in early-type galaxies than the surrounding environment and the field, as expected from the morphology-density relation and from the selection of groups of red galaxies. Furthermore, our work supports the existence of two sub-classes of structures, the first one being formed by compact and isolated groups and the second formed by extended structures. We suggest that while the first class of objects dwells in less dense regions like the outer parts of clusters or the field, possibly sharing the properties of Hickson Compact Groups, the more extended structures represent a mixture of [core+halo] configurations and cores of rich clusters. X-ray luminosities for SHKs are generally consistent with these results and with the expectations for the L_X-sigma_v relation, but also suggest the velocity dispersions reported in literature are underestimated for some of the richest systems.Comment: 20 pages, 14 figures, 4 tables. Accepted for publication by MNRA

Willingness-to-Pay for Genetic Attributes in Aquaculture Industries

The genetic make-up of fish stocks is an important factor in aquaculture production. Choice-based conjoint analysis is used to determine importance of genetic improvements to grow-out producers and an estimated willingness-to-pay for selected attributes. Results from a national survey of aquaculture producers, reveal growth rate as the most important attribute.Resource /Energy Economics and Policy,