59 research outputs found

    Detection of Anomalous Microwave Emission in the Pleiades Reflection Nebula with WMAP and the COSMOSOMAS Experiment

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    We present evidence for anomalous microwave emission (AME) in the Pleiades reflection nebula, using data from the seven-year release of the Wilkinson Microwave Anisotropy Probe (WMAP) and from the COSMOSOMAS experiment. The flux integrated in a 1-degree radius around R.A.=56.24^{\circ}, Dec.=23.78^{\circ} (J2000) is 2.15 +/- 0.12 Jy at 22.8 GHz, where AME is dominant. COSMOSOMAS data show no significant emission, but allow to set upper limits of 0.94 and 1.58 Jy (99.7% C.L.) respectively at 10.9 and 14.7 GHz, which are crucial to pin down the AME spectrum at these frequencies, and to discard any other emission mechanisms which could have an important contribution to the signal detected at 22.8 GHz. We estimate the expected level of free-free emission from an extinction-corrected H-alpha template, while the thermal dust emission is characterized from infrared DIRBE data and extrapolated to microwave frequencies. When we deduct the contribution from these two components at 22.8 GHz the residual flux, associated with AME, is 2.12 +/- 0.12 Jy (17.7-sigma). The spectral energy distribution from 10 to 60 GHz can be accurately fitted with a model of electric dipole emission from small spinning dust grains distributed in two separated phases of molecular and atomic gas, respectively. The dust emissivity, calculated by correlating the 22.8 GHz data with 100-micron data, is found to be 4.36+/-0.17 muK/MJy/sr, a value that is rather low compared with typical values in dust clouds. The physical properties of the Pleiades nebula indicate that this is indeed a much less opaque object than others were AME has usually been detected. This fact, together with the broad knowledge of the stellar content of this region, provides an excellent testbed for AME characterization in physical conditions different from those generally explored up to now.Comment: Accepted for publication in ApJ. 12 pages, 8 figure

    The Atacama Cosmology Telescope: CO(J = 3 - 2) mapping and lens modeling of an ACT-selected dusty star-forming galaxy

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    We report Northern Extended Millimeter Array (NOEMA) CO(J=32J = 3 - 2) observations of the dusty star-forming galaxy ACT-S\,J020941+001557 at z=2.5528z = 2.5528, which was detected as an unresolved source in the Atacama Cosmology Telescope (ACT) equatorial survey. Our spatially resolved spectral line data support the derivation of a gravitational lens model from 37 independent velocity channel maps using a pixel-based algorithm, from which we infer a velocity-dependent magnification factor μ722\mu \approx 7-22 with a luminosity-weighted mean \left\approx 13. The resulting source-plane reconstruction is consistent with a rotating disk, although other scenarios cannot be ruled out by our data. After correction for lensing, we derive a line luminosity LCO(32)=(5.53±0.69)×1010Kkms1pc2L^{\prime}_{\rm CO(3-2)}= (5.53\pm 0.69) \times 10^{10}\,{\rm \,K\,km\,s^{-1}\,pc^{2}}, a cold gas mass Mgas=(3.86±0.33)×1010MM_{{\rm gas}}= (3.86 \pm 0.33) \times 10^{10}\,M_{\odot}, a dynamical mass Mdynsin2i=3.91.5+1.8×1010MM_{\rm dyn}\,{\rm sin}^2\,i = 3.9^{+1.8}_{-1.5} \times 10^{10}\,M_{\odot}, and a gas mass fraction fgascsc2i=1.00.4+0.8f_{\rm gas}\,{\rm csc}^2\,i = 1.0^{+0.8}_{-0.4}. The line brightness temperature ratio of r3,11.6r_{3,1}\approx 1.6 relative to a Green Bank Telescope CO(J=10J=1-0) detection may be elevated by a combination of external heating of molecular clouds, differential lensing, and/or pointing errors.Comment: 8 pages, 5 figures, accepted to Ap

    The QUIJOTE experiment: project status and first scientific results

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    We present the current status of the QUIJOTE (Q-U-I JOint TEnerife) experiment, a new polarimeter with the aim of characterizing the polarization of the Cosmic Microwave Background, and other galactic or extra-galactic physical processes that emit in microwaves in the frequency range 10–42 GHz, and at large angular scales (around 1 degree resolution). The experiment has been designed to reach the required sensitivity to detect a primordial gravitational wave component in the CMB, provided its tensor-to-scalar ratio is larger than r ∼ 0.05. The project consists of two telescopes and three instruments which will survey a large sky area from the Teide Observatory to provide I, Q and U maps of high sensitivity. The first QUIJOTE instrument, known as Multi-Frequency Instrument (MFI), has been surveying the northern sky in four individual frequencies between 10 and 20 GHz since November 2012, providing data with an average sensitivity of 80 µK beam−1 in Q and U in a region of 20, 000 square-degrees. The second instrument, or Thirty-GHz Instrument (TGI), is currently undergoing the commissioning phase, and the third instrument, or Forty-GHz Instrument (FGI), is in the final fabrication phase. Finally, we describe the first scientific results obtained with the MFI. Some specific regions, mainly along the Galactic plane, have been surveyed to a deeper depth, reaching sensitivities of around 40 µK beam−1. We present new upper limits on the polarization of the anomalous dust emission, resulting from these data, in the Perseus molecular complex and in the W43 molecular complex

    The Quijote CMB Experiment

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    We present the current status of the QUIJOTE (Q-U-I JOint TEnerife) CMB Experiment, a new instrument which will start operations early 2009 at Teide Observatory, with the aim of characterizing the polarization of the CMB and other processes of galactic and extragalactic emission in the frequency range 10-30 GHz and at large angular scales. QUIJOTE will be a valuable complement at low frequencies for the PLANCK mission, and will have the required sensitivity to detect a primordial gravitational-wave component if the tensor-to-scalar ratio is larger than r=0.05.Comment: 9 pages, 5 figures. To appear in "Highlights of Spanish Astrophysics V", Proceedings of the VIII Scientific Meeting of the Spanish Astronomical Society (SEA) held in Santander, 7-11 July, 2008. Edited by J. Gorgas, L. J. Goicoechea, J. I. Gonzalez-Serrano, J. M. Dieg

    Salivary cotinine concentrations in daily smokers in Barcelona, Spain: a cross-sectional study

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    Background: Characterizing and comparing the determinant of cotinine concentrations in different populations should facilitate a better understanding of smoking patterns and addiction. This study describes and characterizes determinants of salivary cotinine concentration in a sample of Spanish adult daily smoker men and women. Methods: A cross-sectional study was carried out between March 2004 and December 2005 in a representative sample of 1245 people from the general population of Barcelona, Spain. A standard questionnaire was used to gather information on active tobacco smoking and passive exposure, and a saliva specimen was obtained to determine salivary cotinine concentration. Two hundred and eleven adult smokers (>16 years old) with complete data were included in the analysis. Determinants of cotinine concentrations were assessed using linear regression models. Results: Salivary cotinine concentration was associated with the reported number of cigarettes smoked in the previous 24 hours (R2 = 0.339; p < 0.05). The inclusion of a quadratic component for number of cigarettes smoked in the regression analyses resulted in an improvement of the fit (R2 = 0.386; p < 0.05). Cotinine concentration differed significantly by sex, with men having higher levels. Conclusion: This study shows that salivary cotinine concentration is significantly associated with the number of cigarettes smoked and sex, but not with other smoking-related variables

    The status of the Quijote multi-frequency instrument

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    The QUIJOTE-CMB project has been described in previous publications. Here we present the current status of the QUIJOTE multi-frequency instrument (MFI) with five separate polarimeters (providing 5 independent sky pixels): two which operate at 10-14 GHz, two which operate at 16-20 GHz, and a central polarimeter at 30 GHz. The optical arrangement includes 5 conical corrugated feedhorns staring into a dual reflector crossed-draconian system, which provides optimal cross-polarization properties (designed to be < -35 dB) and symmetric beams. Each horn feeds a novel cryogenic on-axis rotating polar modulator which can rotate at a speed of up to 1 Hz. The science driver for this first instrument is the characterization of the galactic emission. The polarimeters use the polar modulator to derive linear polar parameters Q, U and I and switch out various systematics. The detection system provides optimum sensitivity through 2 correlated and 2 total power channels. The system is calibrated using bright polarized celestial sources and through a secondary calibration source and antenna. The acquisition system, telescope control and housekeeping are all linked through a real-time gigabit Ethernet network. All communication, power and helium gas are passed through a central rotary joint. The time stamp is synchronized to a GPS time signal. The acquisition software is based on PLCs written in Beckhoffs TwinCat and ethercat. The user interface is written in LABVIEW. The status of the QUIJOTE MFI will be presented including pre-commissioning results and laboratory testing

    Epidemiology of tobacco use and dependence in adults in a poor peri-urban community in Lima, Peru

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    <p>Abstract</p> <p>Background</p> <p>Tobacco smoking is an important public health concern worldwide leading to both chronic disease and early death. In Latin America, smoking prevalence is estimated at approximately 30% and prior studies suggest that the prevalence in Peru is 22% to 38%. We sought to determine the prevalence of daily smoking in a poor peri-urban community in Lima, Peru.</p> <p>Methods</p> <p>We conducted a cross-sectional survey in a random sample of adults ≥40 years of age living in Pampas de San Juan de Miraflores, Lima, Peru. We asked participants to respond to a survey that included questions on sociodemographics, tobacco use and dependence.</p> <p>Results</p> <p>We enrolled 316 participants. Average monthly household income was ≤ 400 USD and nearly all homes had running water, sewage, and electricity. Most individuals had not completed high school. Smoking prevalence was 16% overall, yet daily smoking prevalence was 1.9%. Former daily smokers comprised 3.8% of current nonsmokers and 9.1% current occasional smokers. Average scores for the Fagerstrom Test for Nicotine Dependence for daily smokers and occasional smokers were 1.5 and 0, respectively.</p> <p>Conclusions</p> <p>Daily use of tobacco is uncommon among adults in peri-urban communities of Lima, Peru, unlike their counterparts in Lima and other Latin American capital cities. Tobacco dependence is also low. Hence, efforts aimed at primary prevention are of utmost importance in these communities. This study provides an accurate baseline using an internationally recognized assessment tool (Global Adult Tobacco Survey), allowing for accurate assessment of tobacco control interventions over time.</p

    Identification of Plasmodium vivax Proteins with Potential Role in Invasion Using Sequence Redundancy Reduction and Profile Hidden Markov Models

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    BACKGROUND: This study describes a bioinformatics approach designed to identify Plasmodium vivax proteins potentially involved in reticulocyte invasion. Specifically, different protein training sets were built and tuned based on different biological parameters, such as experimental evidence of secretion and/or involvement in invasion-related processes. A profile-based sequence method supported by hidden Markov models (HMMs) was then used to build classifiers to search for biologically-related proteins. The transcriptional profile of the P. vivax intra-erythrocyte developmental cycle was then screened using these classifiers. RESULTS: A bioinformatics methodology for identifying potentially secreted P. vivax proteins was designed using sequence redundancy reduction and probabilistic profiles. This methodology led to identifying a set of 45 proteins that are potentially secreted during the P. vivax intra-erythrocyte development cycle and could be involved in cell invasion. Thirteen of the 45 proteins have already been described as vaccine candidates; there is experimental evidence of protein expression for 7 of the 32 remaining ones, while no previous studies of expression, function or immunology have been carried out for the additional 25. CONCLUSIONS: The results support the idea that probabilistic techniques like profile HMMs improve similarity searches. Also, different adjustments such as sequence redundancy reduction using Pisces or Cd-Hit allowed data clustering based on rational reproducible measurements. This kind of approach for selecting proteins with specific functions is highly important for supporting large-scale analyses that could aid in the identification of genes encoding potential new target antigens for vaccine development and drug design. The present study has led to targeting 32 proteins for further testing regarding their ability to induce protective immune responses against P. vivax malaria
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