Derrick Rodriguez

Learn More
Several proposed source models for Ultra-High Energy Cosmic Rays (UHECRs) consist of dipole distributions oriented towards major astrophysical landmarks such as the galactic center, M87, or Centaurus A. We use a comparison between real data and simulated data to show that the HiRes-I monocular data for energies above 10 18.5 eV is, in fact, consistent with(More)
T135 Comparison of nonlinear functions for describing the growth curve of Nile tilapia Oreochromis niloticus var. chitralada in a commercial production cycle. Mathematical models in fish nutrition have proven indispensable in estimating growth and feed requirements. The aim of this study was to make a statistical comparison of the mathematical growth models(More)
A fundamental question associated with managing historical releases of chlorinated solvents is how DNAPL depletion, or source zone containment, will effect downgradient water quality through time. A common perception is that near-term risks can be addressed through complete DNAPL depletion or source containment. Unfortunately, this is not always true.(More)
We have searched for correlations between the pointing directions of ultrahigh energy cosmic rays observed by the High Resolution Fly's Eye experiment and Active Galactic Nuclei (AGN) visible from its northern hemisphere location. No correlations, other than random correlations, have been found. We report our results using search parameters prescribed by(More)
Air-fluorescence detectors such as the High Resolution Fly's Eye (HiRes) detector are very sensitive to upward-going, Earth-skimming ultrahigh energy electron-neutrino-induced showers. This is due to the relatively large interaction cross sections of these high-energy neutrinos and to the Landau-Pomeranchuk-Migdal (LPM) effect. The LPM effect causes a(More)
A commercial, position-sensitive ion detector was used for the rst time for the time-of-ight ion-cyclotron resonance detection technique in Penning trap mass spectrometry. In this work, the characteristics of the detector and its implementation in a Penning trap mass spectrometer will be presented. In addition, simulations and experimental studies(More)
1 The genus Chaetostoma is a species-rich group of armored catfishes that inhabits rivers and streams in montane forests of South America. Most species of Chaetostoma have been described based on only one or a few specimens from a single river system. Our aim was to determine if the lifting of the Fitzcarrald Arch, 4 Ma, triggered speciation between the(More)
This paper reports the synthesis of silver nanoparticles coated with porous silica (Ag@Silica NPs) using an assisted laser ablation method. This method is a chemical synthesis where one of the reagents (the reducer agent) is introduced in nanometer form by laser ablation of a solid target submerged in an aqueous solution. In a first step, a silicon wafer(More)
An advanced steady state semiconductor laser model is used to analyse the characteristics of high power laser diodes used for pumping erbium doped amplifiers. The laser model solves the bipolar current continuity equations in the bulk and quantum well regions, the thermal conduction equation and the optical wave equation in the travelling wave approximation(More)
  • 1