Latino Protestants and Their Political and Social Engagement (Chapter Six of Latino Protestants in America: Growing and Diverse)

Excerpt: On a rainy early spring morning in a modest brick Presbyterian church just outside the Fruitvale neighborhood of Oakland, California, sixtyfour worshippers gather. The entire worship is in Spanish. During the sermon, the pastor makes a passing reference to how few of the attenders now live in Oakland proper, that many have to drive farther than ever for church services. The implicit message: the leadership of the church realizes that gentrification of San Francisco has spilled over the Bay Bridge and now threatens the availability of affordable housing throughout Oakland. In response, the congregation has started programs that offer legal advice for responding to rent-hiking landlords and identifying housing options around the city. Though resources and attenders tend to be somewhat scarce, the leadership has creatively organized in an effort to address the structural and policy concerns of housing. Beyond that, the pastor proudly notes that this church readily offers immigration status services, computer classes, and English classes

UVMULTIFIT: A versatile tool for fitting astronomical radio interferometric data

The analysis of astronomical interferometric data is often performed on the images obtained after deconvolution of the interferometer's point spread function (PSF). This strategy can be understood (especially for cases of sparse arrays) as fitting models to models, since the deconvolved images are already non-unique model representations of the actual data (i.e., the visibilities). Indeed, the interferometric images may be affected by visibility gridding, weighting schemes (e.g., natural vs. uniform), and the particulars of the (non-linear) deconvolution algorithms. Fitting models to the direct interferometric observables (i.e., the visibilities) is preferable in the cases of simple (analytical) sky intensity distributions. In this paper, we present UVMULTIFIT, a versatile library for fitting visibility data, implemented in a Python-based framework. Our software is currently based on the CASA package, but can be easily adapted to other analysis packages, provided they have a Python API. We have tested the software with synthetic data, as well as with real observations. In some cases (e.g., sources with sizes smaller than the diffraction limit of the interferometer), the results from the fit to the visibilities (e.g., spectra of close by sources) are far superior to the output obtained from the mere analysis of the deconvolved images. UVMULTIFIT is a powerful improvement of existing tasks to extract the maximum amount of information from visibility data, especially in cases close to the sensitivity/resolution limits of interferometric observations.Comment: 10 pages, 4 figures. Accepted in A&A. Code available at http://nordic-alma.se/support/software-tool

DNA repair nucleases

Stability of DNA largely depends on accuracy of repair mechanisms, which remove structural anomalies induced by exogenous and endogenous agents or introduced by DNA metabolism, such as replication. Most repair mechanisms include nucleolytic processing of DNA, where nucleases cleave a phosphodiester bond between a deoxyribose and a phosphate residue, thereby producing 5′-terminal phosphate and 3′-terminal hydroxyl groups. Exonucleases hydrolyse nucleotides from either the 5′ or 3′ end of DNA, while endonucleases incise internal sites of DNA. Flap endonucleases cleave DNA flap structures at or near the junction between single-stranded and double-stranded regions. DNA nucleases play a crucial role in mismatch repair, nucleotide excision repair, base excision repair and double-strand break repair. In addition, nucleolytic repair functions are required during replication to remove misincorporated nucleotides, Okazaki fragments and 3′ tails that may be formed after repair of stalled replication fork

Non-thermal radiation from a runaway massive star

We present a study of the radio emission from a massive runaway star. The star forms a bow shock that is clearly observed in the infrared. We have performed VLA observations under the assumption that the reverse shock in the stellar wind might accelerate charged particles up to relativistic energies. Non-thermal radio emission of synchrotron origin has been detected, confirming the hypothesis. We have then modeled the system and we predict a spectral energy distribution that extends up to gamma-rays. Under some simplifying assumptions, we find that the intensity at high energies is too low to be detected by current instruments, but the future Cherenkov Telescope Array might detect the source.Comment: Accepted for publication in the proceedings of the conference "The multi-wavelength view of Hot, Massive Stars", held in Liege, July 12-16 201

The gamma-ray emitting microquasar LSI+61303

LS I +61 303 is one of the most studied X-ray binary systems because of its two peculiarities: On the one hand being the probable counterpart of the variable gamma ray source 2CG 135+01 (Gregory and Taylor 1978; Tavani et al. 1998) and on the other hand being a periodic radio source (Taylor and Gregory 1982). The recent discovery of a radio emitting jet extending ca. 200 AU at both sides of a central core (Massi et al. 2004) in all evidence has shown the occurrence of accretion/ejection processes in this system. However, the radio outbursts do not occur at periastron passage, where the accretion is at its maximum, but several days later. In addition, when the gamma-ray emission of 2CG 135+01 is examined along the orbital phase of LS I +61 303 one sees that this emission seems to peak at periastron passage (Massi 2004). Here in detail we analyse the trend of the gamma-ray data versus orbital phase and discuss the delay between peaks at gamma-rays and in the radio band within the framework of a two-peak accretion/ejection model proposed by Taylor et al. (1992) and further developed by Marti' and Paredes (1995).Comment: To be published in the proceedings of the Symposium on High-Energy Gamma-Ray Astronomy, Heidelberg, July 26-30, 2004 (AIP Proceedings Series

Optical and near-infrared observations of the microquasar V4641 Sagittarii during the 1999 September outburst

We present photometric and spectroscopic optical and near-infrared (NIR) observations (Based on observations collected at the European Southern Observatory, Chile (ESO ID 63.H-0493 and 64.H-0382)) taken during the outburst of the microquasar V4641 Sgr = SAX J1819.3-2525 (in'tzand et al., 2000) in September 1999. We observed an increase in the J-Ks colour between 5 and 8 days after the outburst, which we interpret as likely evidence for the presence of dust around the source. We also observed an extraordinarily strong, broad and variable H_alpha line, with a velocity width of 4560 km/s suggesting the presence of a high-velocity outflow component. We constrain the distance of the system between 3 and 8 kpc, locating it further away than previously derived from radio observations (Hjellming et al., 2000), but consistent with Orosz et al. (2001). We then discuss the nature of this system, showing that the companion star is either a B3-A2 main sequence star, or a B3-A2 sub-giant crossing the Hertzsprung gap. The system is therefore an Intermediate or High Mass X-ray Binary System (IMXB or HMXB). The distance derived by these optical/NIR observations implies that the jets observed by Hjellming et al. (2000) would then exhibit apparent velocities of ~ 10 c. We finally discuss the possibility of an interaction between the jets and surroundings of the source, and also of this source being a ``microblazar''.Comment: 7 pages, 6 figures, accepted for publication in MNRA