M . A . Bautista

Learn More
A new methodology for constructing calibration sets based on the use of laboratory samples encompassing the same variability sources as production samples was developed. The proposed methodology requires the use of no reference method in order to obtain reference values for the analyte; also, it provides more simple and robust calibration models than does(More)
The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we(More)
document Modeling of iron K lines: radiative and Auger decay data for Fe ii–Fe ix P. Palmeri1Research Associate, Department of Astronomy, University of Maryland, College Park, MD 20742 C. Mendoza1Current address: Centro de F́ısica, IVIC, Caracas 1020A, Venezuela T. R. Kallman 1 M. A. Bautista 2 M. Meléndez 2 NASA Goddard Space Flight Center, Code 662,(More)
Although Galactic cosmic rays (protons and nuclei) are widely believed to be mainly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size-more than 50(More)
We report the discovery of very high energy (VHE) gamma-ray emission from the direction of the SNR G54.1+0.3 using the VERITAS ground-based gamma-ray observatory. The TeV signal has an overall significance of 6.8σ and appears pointlike given the resolution of the instrument. The integral flux above 1 TeV is 2.5% of the Crab Nebula flux and significant(More)
Near Infrared Chemical Imaging (NIR-CI) is demonstrating an increasing interest in pharmaceutical research since it meets the challenging analytical needs of pharmaceutical quality and may serve as a versatile adjunct to conventional NIR spectroscopy in many fields. The direct analysis of samples by using hyperspectral imaging techniques, which provide a(More)
Near infrared (NIR) spectroscopy has been used in a noninvasively mode to develop qualitative and quantitative methods for the monitoring of a wet granulation process. The formulation contained API (10%w/w) and microcrystalline cellulose and maize starch as main excipients. NIR spectra have been acquired through the glass window of the fluidizer in(More)
The purpose of this research was to demonstrate the ability of reflectance near-infrared (NIR) spectroscopy for quantitative analysis of an active ingredient in different production steps of a solid formulation. The drug is quantified at two different steps of a pharmaceutical process: after granulation and after tablet coating. Calibration samples were(More)
Near-infrared spectroscopy (NIRS) has been widely used in the pharmaceutical field because of its ability to provide quality information about drugs in near-real time. In practice, however, the NIRS technique requires construction of multivariate models in order to correct collinearity and the typically poor selectivity of NIR spectra. In this work, a new(More)
Near infrared spectroscopy has proved highly suitable for the analysis of pharmaceutical formulations. However, its limited sensitivity can severely restrict its scope of application. In this work, we determine the active principle and two preservatives in a pharmaceutical preparation available as a hydrogel. The matrix of the pharmaceutical preparation(More)