53 research outputs found
Genotyping Validates the Efficacy of Photographic Identification in a Capture-Mark-Recapture Study Based on the Head Scale Patterns of the Prairie Lizard (\u3ci\u3eSceloporus consobrinus\u3c/i\u3e)
Population studies often incorporate captureâmarkârecapture (CMR) techniques to gather information on longâterm biological and demographic characteristics. A fundamental requirement for CMR studies is that an individual must be uniquely and permanently marked to ensure reliable reidentification throughout its lifespan. Photographic identification involving automated photographic identification software has become a popular and efficient noninvasive method for identifying individuals based on natural markings. However, few studies have (a) robustly assessed the performance of automated programs by using a doubleâmarking system or (b) determined their efficacy for longâterm studies by incorporating multiâyear data. Here, we evaluated the performance of the program Interactive Individual Identification System (I3S) by crossâvalidating photographic identifications based on the head scale pattern of the prairie lizard (Sceloporus consobrinus) with individual microsatellite genotyping (N = 863). Further, we assessed the efficacy of the program to identify individuals over time by comparing error rates between withinâyear and betweenâyear recaptures. Recaptured lizards were correctly identified by I3S in 94.1% of cases. We estimated a false rejection rate (FRR) of 5.9% and a false acceptance rate (FAR) of 0%. By using I3S, we correctly identified 97.8% of withinâyear recaptures (FRR = 2.2%; FAR = 0%) and 91.1% of betweenâyear recaptures (FRR = 8.9%; FAR = 0%). Misidentifications were primarily due to poor photograph quality (N = 4). However, two misidentifications were caused by indistinct scale configuration due to scale damage (N = 1) and ontogenetic changes in head scalation between capture events (N = 1). We conclude that automated photographic identification based on head scale patterns is a reliable and accurate method for identifying individuals over time. Because many lizard or reptilian species possess variable head squamation, this method has potential for successful application in many species
SYNCA: A Synthetic Cyclotron Antenna for the Project 8 Collaboration
Cyclotron Radiation Emission Spectroscopy (CRES) is a technique for measuring the kinetic energy of charged particles through a precision measurement of the frequency of the cyclotron radiation generated by the particle\u27s motion in a magnetic field. The Project 8 collaboration is developing a next-generation neutrino mass measurement experiment based on CRES. One approach is to use a phased antenna array, which surrounds a volume of tritium gas, to detect and measure the cyclotron radiation of the resulting ÎČ-decay electrons. To validate the feasibility of this method, Project 8 has designed a test stand to benchmark the performance of an antenna array at reconstructing signals that mimic those of genuine CRES events. To generate synthetic CRES events, a novel probe antenna has been developed, which emits radiation with characteristics similar to the cyclotron radiation produced by charged particles in magnetic fields. This paper outlines the design, construction, and characterization of this Synthetic Cyclotron Antenna (SYNCA). Furthermore, we perform a series of measurements that use the SYNCA to test the position reconstruction capabilities of the digital beamforming reconstruction technique. We find that the SYNCA produces radiation with characteristics closely matching those expected for cyclotron radiation and reproduces experimentally the phenomenology of digital beamforming simulations of true CRES signals
Viterbi decoding of CRES signals in Project 8
Cyclotron radiation emission spectroscopy (CRES) is a modern approach for determining charged particle energies via high-precision frequency measurements of the emitted cyclotron radiation. For CRES experiments with gas within the fiducial volume, signal and noise dynamics can be modelled by a hidden Markov model. We introduce a novel application of the Viterbi algorithm in order to derive informational limits on the optimal detection of cyclotron radiation signals in this class of gas-filled CRES experiments, thereby providing concrete limits from which future reconstruction algorithms, as well as detector designs, can be constrained. The validity of the resultant decision rules is confirmed using both Monte Carlo and Project 8 data
Tritium Beta Spectrum and Neutrino Mass Limit from Cyclotron Radiation Emission Spectroscopy
The absolute scale of the neutrino mass plays a critical role in physics at
every scale, from the particle to cosmological. Measurements of the tritium
endpoint spectrum have provided the most precise direct limit on the neutrino
mass scale. In this Letter, we present advances by Project 8 to the Cyclotron
Radiation Emission Spectroscopy (CRES) technique culminating in the first
frequency-based neutrino mass limit. With only a cm-scale physical
detection volume, a limit of <180 eV is extracted from the
background-free measurement of the continuous tritium beta spectrum. Using
Kr calibration data, an improved resolution of 1.660.16 eV
(FWHM) is measured, the detector response model is validated, and the
efficiency is characterized over the multi-keV tritium analysis window. These
measurements establish the potential of CRES for a high-sensitivity
next-generation direct neutrino mass experiment featuring low background and
high resolution.Comment: 7 pages, 5 figures, for submission to PR
Half-Dose-Photodynamische Therapie fĂŒr die Behandlung der chronisch-rezidivierenden Retinopathia centralis serosa
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