Clarification of the Nature of the Galaxy CFC97 Cen 05

The galaxy CFC97 Cen 05 has in the past been considered an HI-rich dwarf galaxy in the nearby Centaurus A group. We have used Australia Telescope Compact Array observations to show that the HI associated with CFC97 Cen 05 by Cote et al. (1997) is most likely a Galactic High Velocity Cloud that is centered ~17' from the optical image of the galaxy. At the optical location of the galaxy, which is not that tabulated by Banks et al. (1999), there is no indication of the presence of HI for velocities less than the upper limit of the HIPASS survey at ~12,500 km/s. In addition, WFPC2 images of CFC97 Cen 05 obtained from the HST Archive reveal that this galaxy is in fact not a dwarf at all, but rather is a distant background spiral not associated with the Centaurus A group.Comment: accepted for publication in the PASP (November 2004

The transmutation of dwarf galaxies : stellar populations

Transition-type dwarf (TTD) galaxies share characteristics of early-and late-type dwarfs. Thus, they are suspected to be the thread that connects them. We selected 19 TTD galaxies in the nearby Universe (cz < 2900 km s(-1)) from the Sloan Digital Sky Survey. They span the luminosity range from similar to-14.5 to -19.0 mag in the B band, and are located in different environments. We derive their single stellar population parameters and star formation histories, using the full spectrum fitting technique with two independent population synthesis models. Irrespective of the synthesis models, we find that these dwarfs have a relatively young mean age (around 1-2 Gyr) and low metallicities (similar to-0.7 dex). Moreover, they had approximately constant star formation rates until a few Gyr ago, associated with strong metal enrichment during the first few Gyr of their evolution. We compare these results with the results from Koleva et al., who studied dwarf elliptical (dE) galaxies in the same luminosity range. We find that (1) both samples occupy the same region in the luminosity-metallicity relation, (2) the build-up of the stellar mass in both types of galaxies is very similar, with most of the stars already formed 5 Gyr ago and (3) contrary to the dEs, TTDs are forming stars at present, but after 1 Gyr of passive evolution, their star formation histories would appear identical to that of dEs. As far as the stellar population is concerned, the transformation of TTDs into dEs is definitely possible. A star-forming dwarf galaxy can be stripped of at least a fraction of its gas, and its star formation rate can be reduced to that of the TTDs of the present sample. Continued gas removal may drive a galaxy to the state of a gas-depleted bona fide dE. However, we cannot exclude a scenario where a star-forming galaxy is rapidly transformed into an early type without passing through a noticeable 'transition' phase, as suggested by the relatively small fraction of observed dEs with an interstellar medium. We cannot exclude swinging back and forth between a late-type dwarf and a TTD (in the case of episodic star formation) or an early-type dwarf and a TTD (in the case of gas infall)

Detection of neutral hydrogen in early-type dwarf galaxies of the Sculptor Group

We present our results of deep 21 cm line (HI) observations of five early and mixed-type dwarf galaxies in the nearby Sculptor group using the ATNF 64m Parkes Radio Telescope. Four of these objects, ESO294-G010, ESO410-G005, ESO540-G030, and ESO540-G032, were detected in HI with neutral hydrogen masses in the range of 2-9x10^5 M_{\odot} ($M_{HI}/L_{B}$ = 0.08, 0.13, 0.16, and 0.18, respectively). These HI masses are consistent with the gas mass expected from stellar outflows over a large period of time. Higher resolution radio data from the Australia Telescope Compact Array were further analysed to measure more accurate positions and the distribution of the HI gas. In the cases of dwarfs ESO294-G010 and ESO540-G030, we find significant offsets of 290 pc and 460 pc, respectively, between the position of the HI peak flux and the center of the stellar component. These offsets are likely to have internal cause such as the winds from star-forming regions. The fifth object, the spatially isolated dwarf elliptical Scl-dE1, remains undetected at our 3\sigma limit of 22.5 mJy km/s and thus must contain less than 10^5 M_{\odot} of neutral hydrogen. This leaves Scl-dE1 as the only Sculptor group galaxy known where no interstellar medium has been found to date. The object joins a list of similar systems including the Local Group dwarfs Tucana and Cetus that do not fit into the global picture of the morphology-density relation where gas-rich dwarf irregulars are in relative isolation and gas-deficient dwarf ellipticals are satellites of more luminous galaxies.Comment: 21 pages, 4 figures, to be published in AJ (accepted

Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma as a Bridge to Liver Transplantation: A Retrospective Study

Background. Transcatheter arterial lipiodol chemoembolization (TACE) can be used in cirrhotic patients with hepatocellular carcinoma to avoid tumor progression before transplantation. Objective. To evaluate the efficacy and safety of TACE used as a bridge to liver transplantation. Methods. TACE was performed in 30 cirrhotic patients with hepatocellular carcinoma. Milan criteria were used to select patients for transplant. Patients had a good or moderately impaired liver function, no arterioportal fistulae, and a good portal perfusion. Results. 48 TACE were performed in 30 patients. Before transplantation, 4 patients were dropped off the list due to tumor extension or liver failure. Complete necrosis of the tumor was observed in 11 patients and partial necrosis in 15 patients. After transplantation, 6 patients died and tumor recurrence was observed in 5 patients with a tumor beyond Milan criteria or no response to TACE. Conclusion. TACE is useful as a bridge to liver transplantation in a selected group of cirrhotic patients with hepatocellular carcinoma. A combined therapeutic approach before surgery might improve the prognosis in these patients

The Environmental Influence on the Evolution of Local Galaxies

The results of an Halpha photometric survey of 30 dwarf galaxies of various morphologies in the Centaurus A and Sculptor groups are presented. Of these 30, emission was detected in 13: eight are of late-type, two are early-type and three are of mixed-morphology. The typical flux detection limit of 2e-16 erg s-1 cm-2, translates into a Star Formation Rate (SFR) detection limit of 4e-6 M_sol yr-1 . In the light of these results, the morphology-density relation is reexamined: It is shown that, despite a number of unaccounted parameters, there are significant correlations between the factors determining the morphological type of a galaxy and its environment. Dwarf galaxies in high density regions have lower current SFR and lower neutral gas content than their low density counterparts, confirming earlier results from the Local Group and other denser environments. The effect of environment is also seen in the timescale formed from the ratio of blue luminosity to current SFR - dwarfs in higher density environments have larger values, indicating relatively higher past average SFR. The influence of environment extends very far and no dwarfs from our sample can be identified as 'field' objects.Comment: 23 pages, 9 figures, accepted in A

Relationship between Sponsorship and Failure Rate of Dental Implants: A Systematic Approach

BACKGROUND: The number of dental implant treatments increases annually. Dental implants are manufactured by competing companies. Systematic reviews and meta-analysis have shown a clear association between pharmaceutical industry funding of clinical trials and pro-industry results. So far, the impact of industry sponsorship on the outcomes and conclusions of dental implant clinical trials has never been explored. The aim of the present study was to examine financial sponsorship of dental implant trials, and to evaluate whether research funding sources may affect the annual failure rate. METHODS AND FINDINGS: A systematic approach was used to identify systematic reviews published between January 1993 and December 2008 that specifically deal with the length of survival of dental implants. Primary articles were extracted from these reviews. The failure rate of the dental implants included in the trials was calculated. Data on publication year, Impact Factor, prosthetic design, periodontal status reporting, number of dental implants included in the trials, methodological quality of the studies, presence of a statistical advisor, and financial sponsorship were extracted by two independent reviewers (kappa = 0.90; CI(95%) [0.77-1.00]). Univariate quasi-Poisson regression models and multivariate analysis were used to identify variables that were significantly associated with failure rates. Five systematic reviews were identified from which 41 analyzable trials were extracted. The mean annual failure rate estimate was 1.09%.(CI(95%) [0.84-1.42]). The funding source was not reported in 63% of the trials (26/41). Sixty-six percent of the trials were considered as having a risk of bias (27/41). Given study age, both industry associated (OR = 0.21; CI(95%) [0.12-0.38]) and unknown funding source trials (OR = 0.33; (CI(95%) [0.21-0.51]) had a lower annual failure rates compared with non-industry associated trials. A conflict of interest statement was disclosed in 2 trials. CONCLUSIONS: When controlling for other factors, the probability of annual failure for industry associated trials is significantly lower compared with non-industry associated trials. This bias may have significant implications on tooth extraction decision making, research on tooth preservation, and governmental health care policies

Interstellar medium disruption in the Centaurus A group

We present the results of a 21 cm neutral hydrogen (HI) line detection experiment in the direction of 18 low luminosity dwarf galaxies of the Centaurus A group, using the Australia Telescope National Facility 64m Parkes Radio Telescope and the Australia Telescope Compact Array. Five dwarfs have HI masses between M_HI=4x10^5 to M_HI=2.1x10^7 Msol and 0.04<M_HI/L_B<1.81 Msol L_{sol, B}^-1. The other 13 have upper-limits between M_HI<5x10^5 and M_HI<4x10^6 Msol (M_HI}/L_B<0.24 Msol L_{sol, B}^-1). Two of the mixed-morphology dwarfs remain undetected in HI, a situation that is in contrast to that of similar Local Group and Sculptor group objects where all contain significant amounts of neutral gas. There is a discontinuity in the HI properties of Centaurus A group low luminosity dwarfs that is unobserved amongst Sculptor group dwarfs. All objects fainter than M_B=-13 have either M_HI>10^7 Msol or M_HI<10^6 Msol. This gap may be explained by the ram pressure stripping mechanism at work in this dense environment where all galaxies with M_HI<10^7 Msol have been stripped of their gas. The required intergalactic medium density to achieve this is ~10^-3 cm^-3.Comment: 7 figures, 2 table

The HI environment of the Sculptor dwarf spheroidal galaxy

New observations of the neutral hydrogen (HI) in and around the line of sight of the Sculptor dwarf spheroidal (dSph) are presented. The data obtained with the single-dish Parkes telescope cover a large area of 7\degr x 7\degr in the direction of the dwarf, and have resolutions of 15\farcm x 1.12 km/s. The Australia Telescope Compact Array (ATCA) was used to map a smaller area of 2\degr x 2\degr centered on the direction of the dwarf with higher resolutions (350\arcsec x 140\arcsec x 1.65 km/s). Many HI structures having velocities outside the range of the normal Galactic disk velocities were detected, including the two Sculptor clouds (northeast and southwest) of Carignan et al. (1998, C98). The present study shows the total extent of the C98 clouds. We derived heliocentric radial velocities for the NE and SW clouds of 100.2\pm 0.9 km/s and 105.1\pm 0.3 km/s, respectively. The intensity-weighted mean HI velocity for both clouds is 104.1\pm 0.4 km/s. The mass of each cloud is (4.1\pm 0.2) x 10^4 M_\odot (NE cloud) and (1.93\pm 0.02) x 10^5 M_\odot (SW cloud) at the Sculptor dSph distance (79 kpc).Comment: 21 pages, 7 figures, to be published in A

A text-independent speaker authentication system for mobile devices

This paper presents a text independent speaker authentication method adapted to mobile devices. Special attention was placed on delivering a fully operational application, which admits a sufficient reliability level and an efficient functioning. To this end, we have excluded the need for any network communication. Hence, we opted for the completion of both the training and the identification processes directly on the mobile device through the extraction of linear prediction cepstral coefficients and the naive Bayes algorithm as the classifier. Furthermore, the authentication decision is enhanced to overcome misidentification through access privileges that the user should attribute to each application beforehand. To evaluate the proposed authentication system, eleven participants were involved in the experiment, conducted in quiet and noisy environments. Public speech corpora were also employed to compare this implementation to existing methods. Results were efficient regarding mobile resources’ consumption. The overall classification performance obtained was accurate with a small number of samples. Then, it appeared that our authentication system might be used as a first security layer, but also as part of a multilayer authentication, or as a fall-back mechanism