Measuring Galaxy Star Formation Rates From Integrated Photometry: Insights from Color-Magnitude Diagrams of Resolved Stars

We use empirical star formation histories (SFHs), measured from HST-based resolved star color-magnitude diagrams, as input into population synthesis codes to model the broadband spectral energy distributions (SEDs) of ~50 nearby dwarf galaxies (6.5 < log M/M_* < 8.5, with metallicities ~10% solar). In the presence of realistic SFHs, we compare the modeled and observed SEDs from the ultraviolet (UV) through near-infrared (NIR) and assess the reliability of widely used UV-based star formation rate (SFR) indicators. In the FUV through i bands, we find that the observed and modeled SEDs are in excellent agreement. In the Spitzer 3.6micron and 4.5micron bands, we find that modeled SEDs systematically over-predict observed luminosities by up to ~0.2 dex, depending on treatment of the TP-AGB stars in the synthesis models. We assess the reliability of UV luminosity as a SFR indicator, in light of independently constrained SFHs. We find that fluctuations in the SFHs alone can cause factor of ~2 variations in the UV luminosities relative to the assumption of a constant SFH over the past 100 Myr. These variations are not strongly correlated with UV-optical colors, implying that correcting UV-based SFRs for the effects of realistic SFHs is difficult using only the broadband SED. Additionally, for this diverse sample of galaxies, we find that stars older than 100 Myr can contribute from <5% to100% of the present day UV luminosity, highlighting the challenges in defining a characteristic star formation timescale associated with UV emission. We do find a relationship between UV emission timescale and broadband UV-optical color, though it is different than predictions based on exponentially declining SFH models. Our findings have significant implications for the comparison of UV-based SFRs across low-metallicity populations with diverse SFHs.Comment: 22 pages, 15 figures, ApJ accepte

Adenomatoid odontogenic tumor associated to reactive fibro-osseous lesion: a case report

An adenomatoid odontogenic tumor (AOT) is a benign epithelial lesion, being the fourth most common among all odontogenic tumors. Usually presents as slow painless growth that sometimes leads to facial asymmetry. Many cases are detected by radiographic studies, and the indication for biopsy and surgery is secondary to this finding.We report a case of a 17-year-old man with a history of left mandibular painless swelling since 4 months ago, associated with facial asymmetry and hard consistency. An imaging study showed an extensive unilocular radiolucent lesion to the basilar arch, with defined limits and with peripheral hyperdense areas located only vestibular to the lesion. The histopathology was composed of odontogenic epithelial cell proliferation, with epithelial nodular and duct-like structures, rosettes of spindled epithelial cells with eosinophilic material, calcifications, and fibro-osseous reaction. Surgical conservative excision including the affected tooth is the treatment of choice and recurrence is rare. The histologic findings of reactive fibro-osseous proliferation in AOT should be interpreted as a reactive change in the tumor capsule and not as an adnexal lesion.We present an atypical case of AOT with reactive fibro-osseous reaction. Despite clinical aggressive behavior, conservative surgical treatment could be the treatment of choice. Additionally, we emphasize the importance of histopathological examination together with the imaging study of radiolucent lesions of the maxillary bones

Angiographic evidence for reduced graft patency due to competitive flow in composite arterial T-grafts

ObjectiveComposite arterial grafting causes splitting of internal thoracic artery flow to various myocardial regions. The amount of flow supplying each region depends on the severity of coronary stenosis. Competitive flow in the native coronary artery can cause occlusion or severe narrowing of the internal thoracic artery supplying this coronary vessel.MethodsTwo hundred three consecutive postoperative coronary angiographies of 163 patients who underwent bilateral internal thoracic artery grafting using the composite-T-graft technique were analyzed. Angiographies were done in symptomatic patients or in patients with positive thalium scan between 2 and 102 months after surgery and were compared with preoperative angiograms.ResultsIn 123 patients, both internal thoracic arteries were patent. The remaining 40 control patients had at least 1 nonfunctioning internal thoracic artery. A lower stenosis rate in the left anterior and circumflex arteries was associated with higher occlusion rate of the left internal thoracic artery (P < .005) and the right internal thoracic artery (P < .005), respectively. In 19 angiograms of 18 patients, graft failure could be related to competitive flow. This included 7 patients with disease of the left main artery and a preoperative stenosis degree ranging between 50% and 80%, 8 patients with moderate stenosis (70% or less) of the circumflex artery, and 3 with moderate stenosis of the left anterior descending artery. Three of the patients with disease of the left main artery, 2 of the patients with competitive flow in the circumflex artery, and all patients in the subgroup with left anterior descending arterial disease underwent percutaneous or surgical reintervention.ConclusionThe composite T-graft technique of bilateral internal thoracic artery grafting should be reserved for patients with severe (70% or more) left anterior descending and circumflex arterial stenosis

A GALEX Ultraviolet Imaging Survey of Galaxies in the Local Volume

We present results from a GALEX ultraviolet (UV) survey of a complete sample of 390 galaxies within ~11 Mpc of the Milky Way. The UV data are a key component of the composite Local Volume Legacy (LVL), an ultraviolet-to-infrared imaging program designed to provide an inventory of dust and star formation in nearby spiral and irregular galaxies. The ensemble dataset is an especially valuable resource for studying star formation in dwarf galaxies, which comprise over 80% of the sample. We describe the GALEX survey programs which obtained the data and provide a catalog of far-UV (~1500 Angstroms) and near-UV (~2200 Angstroms) integrated photometry. General UV properties of the sample are briefly discussed. We compute two measures of the global star formation efficiency, the SFR per unit HI gas mass and the SFR per unit stellar mass, to illustrate the significant differences that can arise in our understanding of dwarf galaxies when the FUV is used to measure the SFR instead of H-alpha. We find that dwarf galaxies may not be as drastically inefficient in coverting gas into stars as suggested by prior H-alpha studies. In this context, we also examine the UV properties of late-type dwarf galaxies that appear to be devoid of star formation because they were not detected in previous H-alpha narrowband observations. Nearly all such galaxies in our sample are detected in the FUV, and have FUV SFRs that fall below the limit where the H-alpha flux is robust to Poisson fluctuations in the formation of massive stars. The UV colors and star formation efficiencies of H-alpha-undetected, UV-bright dwarf irregulars appear to be relatively unremarkable with respect to those exhibited by the general population of star-forming galaxies.Comment: submitted to ApJS, revised per referee's comments; accepted Oct. 30 w/o further revision; 37 pages; figure 6 omitted due to size; figure available from http://users.obs.carnegiescience.edu/jlee/paper

Framework de Composição Musical Algorítmica

Este artigo descreve o projeto de um framework para composição musical algorítmica, uma ferramenta que se propõe a reproduzir o processo de composição musical através de recursos computacionais. O sistema permite a inclusão de algoritmos de composição responsáveis por criar trechos musicais de acordo com um conjunto de parâmetros previamente especificados. Dessa forma, o recurso pode ser acoplado a agentes externos, como aplicações e jogos eletrônicos, podendo seus resultados ser manipulados e assim atender sua demanda específica.

The GALEX/S4G UV-IR color-color diagram: Catching spiral galaxies away from the Blue Sequence

We obtained GALEX FUV, NUV, and Spitzer/IRAC 3.6$\mu$m photometry for > 2000 galaxies, available for 90% of the S4G sample. We find a very tight "GALEX Blue Sequence (GBS)" in the (FUV-NUV) versus (NUV-[3.6]) color-color diagram which is populated by irregular and spiral galaxies, and is mainly driven by changes in the formation timescale ($\tau$) and a degeneracy between $\tau$ and dust reddening. The tightness of the GBS provides an unprecedented way of identifying star-forming galaxies and objects that are just evolving to (or from) what we call the "GALEX Green Valley (GGV)". At the red end of the GBS, at (NUV-[3.6]) > 5, we find a wider "GALEX Red Sequence (GRS)" mostly populated by E/S0 galaxies that has a perpendicular slope to that of the GBS and of the optical red sequence. We find no such dichotomy in terms of stellar mass (measured by $\rm{M}_{[3.6]}$), since both massive ($M_{\star} > 10^{11} M_{\odot}$) blue and red sequence galaxies are identified. The type that is proportionally more often found in the GGV are the S0-Sa's and most of these are located in high-density environments. We discuss evolutionary models of galaxies that show a rapid transition from the blue to the red sequence on timescale of $10^{8}$years.Comment: 7 pages, 4 figures, 1 table. Accepted for publication in ApJ

Fidelity, entanglement, and information complementarity relation

We investigate the dynamics of information in isolated multi-qubit systems. It is shown that information is in not only local form but also nonlocal form. We apply a measure of local information based on fidelity, and demonstrate that nonlocal information can be directly related to some appropriate well defined entanglement measures. Under general unitary transformations, local and nonlocal information will exhibit unambiguous complementary behavior with the total information conserved.Comment: 5 pages, 3 figure

Entangled Electronic States in Multiple Quantum-Dot Systems

We present an analytically solvable model of $P$ colinear, two-dimensional quantum dots, each containing two electrons. Inter-dot coupling via the electron-electron interaction gives rise to sets of entangled ground states. These ground states have crystal-like inter-plane correlations and arise discontinously with increasing magnetic field. Their ranges and stabilities are found to depend on dot size ratios, and to increase with $P$.Comment: To appear in Physical Review B (in press). RevTeX file. Figures available from [email protected]

Long-term outcomes of coronary artery bypass grafting patients supported preoperatively with an intra-aortic balloon pump

ObjectiveMost studies describing the outcome of coronary artery bypass grafting patients supported preoperatively with an intra-aortic balloon pump (IABP) have reported early results. The purpose of our study was to evaluate the early and long-term results.MethodsOf 2658 isolated coronary artery bypass grafting procedures performed from 1996 to 2001, 215 were supported preoperatively with an IABP. The indications for IABP insertion were cardiogenic shock in 18 (8.4%), acute evolving myocardial infarction in 38 (17.7%), clinical instability in 84 (39.1%), and critical coronary lesions in 75 (34.9%).ResultsOperative mortality was 12.6%. The mortality of the cardiogenic shock patients was greater (22.2%; P = .174). Logistic regression analysis showed patient age (odds ratio, 1.057; 95% confidence interval, 1.010-1.108) and cardiopulmonary bypass (CPB) time (odds ratio, 1.020; 95% confidence interval, 1.008-1.031) were associated with increased operative mortality. An increased number of bypass grafts had a protective effect (odds ratio, 0.241; 95% confidence interval, 0.113-0.515). The actual early mortality was lower than the logistic EuroSCORE calculated mortality (12.6% vs 32.8%, P < .0001). The mean follow-up was 8 ± 4 years. The Kaplan-Meier 10-year survival was 49%. The Cox adjusted overall (early and late) survival and major adverse cardiac events-free survival of the different IABP subgroups was similar. Cox analyses showed peripheral vascular disease, off-pump coronary artery bypass surgery, age, CPB time, female gender, and fewer bypass grafts were associated with decreased survival.ConclusionsIn patients supported preoperatively with an IABP, better early and long-term results were strongly related to younger age, a shorter CPB time, and a greater number of bypass grafts. Avoiding the use of CPB (off pump) in these emergency cases is not recommended