INANOE Repositorio (Inst- Nacional de Astrofísica, Óptica y Electrónica
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Obscured star formation in Lyα blobs at z = 3.1
Get PDFWe present results from the AzTEC/ASTE 1.1-mm imaging survey of 35 Lyα blobs (LABs) found in the SSA22 protocluster at z = 3.1. These 1.1-mm data reach an rms noise level of 0.7–1 mJy beam⁻¹, making this the largest millimetre-wave survey of LABs to date. While one (or possibly two) out of 35 LABs might be detected at 3σ level, no significant (≥3.5σ) emission is found in any of individual 35 LABs. From this, we estimate 3σ upper limits on the far-infrared luminosity of LFIR < 2 × 10¹² L๏ (the dust temperature of 35K and the emissivity index of 1.5 are assumed). Stacking analysis reveals that the 1.1-mm flux density averaged over the LABs is S₁.₁mm < 0.40 mJy (3σ), which places a constraint of LFIR< 4.5 × 10¹¹ L๏. These data constrain the dust spectral energy distributions of the LABs more tightly than ever if their spectral indices at rest-frame wavelength of ≈ 240 μm are similar to those found in (ultra-)luminous infrared galaxies at 0.2 < z < 0.3. Our results suggest that LABs on average have little ultraluminous obscured star formation, in contrast to a long-believed picture that LABs undergo an intense episode of dusty star formation activities with star formation rates of ∼10³M๏ yr⁻¹. Observations with the Atacama Large Millimeter/submillimeter Array are needed to directly study the obscured part of star formation activity in the LABs
FinFET SRAM hardening through design and technology parameters considering process variations
Get PDFRadiation-induced soft errors have become one of the most important reliability concerns in the nanometer regime. In this paper, we analyze two alternatives to improve FinFET-based SRAM cell hardening. One is related to increasing the number of fins of the transistors composing the cross-coupled inverters. This option provides a significant increase of the cell critical charge (Qcrit), but with a cost in area. The other alternative increases the transistors fin height. Results show that a similar Qcrit gain is achieved by increasing the fin height instead of the number of fins without area overhead. The impact of process variations has been considered. Qcrit distribution has been modeled through an statistical approach based on Design of Experiments. Results are presented for a 10nm-SOI Trigate FinFET technology
¿Es posible incrementar la sensibilidad diagnóstica de una radiografía?
Get PDFIntroduction. The qualities that digital x-rays possess, and which analog x-ray lack, are unquestionable. In an effort to obtain analogic x-rays that have the same qualities, wehave
implemented a technique that uses the photographic process and digital processing of images. Using them individually or simultaneously, depending on the problem, we have found that sensitivity can be increased to the point where it is possible to view details that would be difficult to see otherwise. At times high resolution is also needed, and thus far we have achieved 10 microns; however, that value can be improved in the near future usingh igher resolution detectors. We show theresults of applying the technique in four cases.
Material and methods. The x-rays were photographed using a CCD (charge coupled device) camera and a fixed focal distance lens. Controlling the diameter of the diaphragm, we obtained contrasted images even when the x-ray is dark or bright. Changing the distance between the camera and the x-ray we controlled the size of the photographed area. The pixel size of the CCD camera is 3 microns and the size of the digitalized images is 3000 × 2200 pixels. The maximum resolution obtained is 10 microns for an x-ray area of 30 × 25 mm. To show some of the advantages of the technique, four cases were analyzed: rheumatoid arthritis, osteopenia, breast cancer, and calcifications.Introducción. Son indiscutibles las cualidades que tienen las radiografías digitales que no poseen las radiografías analógicas. En un afán de que las radiografías analógicas cuenten también con esas características hemos implementado una técnica que utiliza el proceso fotográfico y el procesado digital de imágenes. Usándolas de manera individual o simultáneamente, dependiendo del problema, hemos encontrado que se puede mejorar la sensibilidad de la radiografía de tal manera que es posible visualizar detalles que de otra manera seria difícil apreciar. En ocasiones es necesario contar también con una buena resolución y hasta este momento hemos alcanzado 10 micras; sin embargo, este valor podría mejorarse en un futuro no lejano con detectores de mayor resolución. Se muestran los resultados de aplicar la técnica en cuatro casos.
Material y métodos. Usando una cámara CCD (charge coupled device o dispositivo de cargas acopladas) y una lente de distancia focal fija se fotografían las radiografías. Controlando el diámetro del diafragma obtenemos imágenes contrastadas aun cuando la radiografía este oscura o brillante. Modificando la distancia entre la cámara y la radiografía controlamos el tamaño del área fotografiada. El tamaño del pixel de la cámara CCD es de 3 micras y el tamaño de las imagines digitalizadas es de 3 000 × 2 200 pixeles. La resolución máxima obtenida es de 10 micras para un área de la radiografía de 30 × 25 mm. Para mostrar algunas de las ventajas de la técnica se analizaron cuatro casos: artritis reumatoide, osteopenia, cáncer de mama y calcificaciones
All-fiber multimode interference micro-displacement sensor
Get PDFWe report an all-fiber micro-displacement sensor based on multimode interference (MMI) effects. The micro-displacement sensor consists of a segment of No-Core multimode fiber (MMF) with one end spliced to a segment of single mode fiber (SMF) which acts as the input. The other end of the MMF and another SMF are inserted into a capillary ferrule filled with index matching liquid. Since the refractive index of the liquid is higher than that of the ferrule, a liquid MMF with a diameter of 125 μm is formed between the fibers inside the ferrule. When the fibers are separated this effectively increases the length of the MMF. Since the peak wavelength response of MMI devices is very sensitive to changes in the MMF’s length, this can be used to detect micro-displacements. By measuring spectral changes we have obtained a sensing range of 3 mm with a sensitivity of 25 nm mm−1 and a resolution of 20 μm. The sensor can also be used to monitor small displacements by using a single wavelength to interrogate the transmission of the MMI device close to the resonance peak. Under this latter regime we were able to obtain a sensitivity of 7000 mV mm−1 and a sensing range of 100 μm, with a resolution up to 1 μm. The simplicity and versatility of the sensor make it very suitable for many diverse applications
Non-linear joint transform correlator for micro-displacement measurement using speckle patterns
No full textThis work presents a procedure for measuring displacements of tens micrometer, in one and two dimensions, based on the correlation between two speckle patterns. For this purpose, two objective speckle patterns are recorded by a digital camera –one before and one after the object has been moved- and placed in the input plane of nonlinear joint transform correlator. Nonlinear transformation of the joint power spectrum allows a sharper correlation peak and a high signal to noise ratio. The autocorrelation peak coordinates of the first pattern are set as a reference for measuring shifts of the successive cross-correlation peak. One criterion for reliable measure is proposed. Results related with different distances sample-sensor and illuminating wavelengths at 632.8 nm and 543.5 nm are presented.Se presenta un procedimiento para medir desplazamiento en el rango de micrones, en una y dos dimensiones, basado en la correlación conjunta de patrones de speckle (moteado característico de la superficie iluminada por un láser). Para este propósito, dos patrones de speckle por propagación libre, registrados por una cámara digital, uno antes y otro después del movimiento de la superficie objeto, se colocan en el plano de entrada de un correlador de transformada conjunta. Una transformación no lineal de la densidad espectral de energía logra una alta razón señal a ruido en el plano de salida del correlador. Las coordenadas del pico de autocorrelación, del primer patrón se colocan como origen para medir los desplazamientos sucesivos del pico de correlación cruzada. Se propone un criterio para determinar el rango de medida confiable y se presentan algunos resultados para diferentes distancias superficie-sensor y longitud de onda del láser
CHARACTERIZATION OF A SAMPLE OF INTERMEDIATE-TYPEAGN. II. Host Bulge Properties and Black Hole Mass Estimates
No full textWe present a study of the host bulge properties and their relations with the blackhole mass on a sample of 10 intermediate-type active galactic nuclei (AGN). Our sample consists mainly of early type spirals, four of them hosting a bar. For 70⁺¹⁰₋₁₇% of thegalaxies we have been able to determine the type of the bulge, and find that these objects probably harbor a pseudobulge or a combination of classical bulge/ pseudobulge, suggesting that pseudobulges mightbe frequent in intermediate-typeAGN. In our sample, 50 ± 14% of the objects show double-peaked emission lines. Therefore, narrowdouble-peaked emission lines seem to be frequent in galaxies harboring a pseudobulgeor a combination of classical bulge/ pseudobulge. Depending on the bulge type, we estimated the black hole mass using the corresponding MBH -σ*relation and found them with a range of: 5.69±0.21 <log Mσ*BH <8.09±0.24. Comparing these Mσ*BH values with masses derived from the FWHM of Hβ and the continuum luminosity at 5100 Å from their SDSS-DR7 spectra (MBH) we find that eight out of ten (80⁺⁷₋₁₇%) galaxies have black hole masses that are compatible within a factor of 3.This result would support that MBH and Mσ*BH are the same for intermediate-typeAGN as has been found for type 1 AGN. However, when the type of the bulge istaken into account only 3 out of the 7 (43⁺¹⁸₋₁₅%) objects of the sample have their Mσ*BH and MBH compatible within 3-σ errors. We also find that estimations basedon the MBH–σ*relation for pseudobulges are not compatible in 50±20% of theobjects
Herschel observations of the debris disc around HIP 92043*
No full textContext. Typical debris discs are composed of particles ranging from several micron sized dust grains to km sized asteroidal bodies, and their infrared emission peaks at wavelengths 60–100 μm. Recent Herschel DUNES observations have identified several debris discs around nearby Sun-like stars (F, G and K spectral type) with significant excess emission only at 160 μm.
Aims.We observed HIP 92043 (110 Her, HD 173667) at far-infrared and sub-millimetre wavelengths with Herschel PACS and SPIRE. Identification of the presence of excess emission from HIP 92043 and the origin and physical properties of any excess was undertaken through analysis of its spectral energy distribution (SED) and the PACS images.
Methods. The PACS and SPIRE images were produced using the HIPE photProject map maker routine. Fluxes were measured using aperture photometry. A stellar photosphere model was scaled to optical and near infrared photometry and subtracted from the farinfared and sub-mm fluxes to determine the presence of excess emission. Source radial profiles were fitted using a 2D Gaussian and compared to a PSF model based on Herschel observations of α Boo to check for extended emission.
Results. Clear excess emission from HIP 92043 was observed at 70 and 100 μm. Marginal excess was observed at 160 and 250 μm. Analysis of the images reveals that the source is extended at 160 μm. A fit to the source SED is inconsistent with a photosphere and single temperature black body.
Conclusions. The excess emission from HIP 92043 is consistent with the presence of an unresolved circumstellar debris disc at 70 and 100 μm, with low probability of background contamination. The extended 160 μm emission may be interpreted as an additional cold component to the debris disc or as the result of background contamination along the line of sight. The nature of the 160 μm excess cannot be determined absolutely from the available data, but we favour a debris disc interpretation, drawing parallels with previously identified cold disc sources in the DUNES sample
Deleterious effect of suboptimal diet on rest-activity cycle in Anastrepha ludens manifests itself with age
Get PDFActivity patterns and sleep-wake cycles are among the physiological processes that change most prominently as animals age, and are often good indicators of healthspan. In this study, we used the video-based high-resolution behavioral monitoring system (BMS) to monitor the daily activity cycle of tephritid fruit flies Anastrepha ludens over their lifetime. Surprisingly, there was no dramatic change in activity profile with respect to age if flies were consistently fed with a nutritionally balanced diet. However, if flies were fed with sugar-only diet, their activity profile decreased in amplitude at old age, suggesting that suboptimal diet affected activity patterns, and its detrimental effect may not manifest itself until the animal ages. Moreover, by simulating different modes of behavior monitoring with a range of resolution and comparing the resulting conclusions, we confirmed the superior performance of video-based monitoring using high-resolution BMS in accurately representing activity patterns in an insect model
The atacama cosmology telescope: cosmological parameters from three seasons of data.
No full textWe present constraints on cosmological and astrophysical parameters from high-resolution microwave background maps at 148 GHz and 218 GHz made by the Atacama Cosmology Telescope (ACT) in three seasons of observations from 2008 to 2010. A model of primary cosmological and secondary foreground parameters is fit to the map power spectra and lensing deflection power spectrum, including contributions from both the thermal Sunyaev-Zeldovich (tSZ) effect and the kinematic Sunyaev-Zeldovich (kSZ) effect, Poisson and correlated anisotropy from unresolved infrared sources, radio sources, and the correlation between the tSZ effect and infrared sources. The power ℓ²Cl /2π of the thermal SZ power spectrum at 148 GHz is measured to be 3.4±1.4 μK² at ℓ = 3000; while the corresponding amplitude of the kinematic SZ power spectrum has a 95% confidence level upper limit of 8.6 μK². Combining ACT power spectra with the WMAP 7-year temperature and polarization power spectra, we find excellent consistency with the LCDM model. We constrain the number of effective relativistic degrees of freedom in the early universe to be Neff = 2.79 ± 0.56, in agreement with the canonical value of Neff = 3.046 for three massless neutrinos. We constrain the sum of the neutrino masses to be Σmv < 0.39 eV at 95% confidence when combining ACT and WMAP 7-year data with BAO and Hubble constant measurements. We constrain the amount of primordial helium to be Yp = 0.225±0.034, and measure no variation in the fine structure constant α since recombination, with α/α₀ = 1.004 ± 0.005. We also find no evidence for any running of the scalar spectral index, dns/d ln k = -0.004 ± 0.012
Electrical characterization of planarized a-SiGe:H Thin-film Transistors
Get PDFIn this work the electrical characterization of n-channel a-SiGe:H TFTs with planarized gate electrode is presented. The planarized a-SiGe:H TFTs were fabricated at 200°C on corning glass substrate. The devices exhibit a subthreshold slope of 0.56 V/Decade, an on/off-current ratio approximately of 10⁶ and off-current approximately of 0.3x10⁻¹² A. The results show an improvement of the electrical characteristics when are compared to those unplanarized devices fabricated at higher temperature. Moreover, the simulation of the device using a SPICE model is presented