2,317 research outputs found
Avon Park Air Force Range project: distribution and abundance of sensitive wildlife species at Avone Park Force Range
Executive Summary. We surveyed for seven species ofsensitve wildlife (Florida gopher frogs,
gopher tortoise, eastern indigo snake, eastern diamondback rattlesnake, Florida mouse, Florida
roundtail muskrat, Sherman's fox squirrel) between October 1996 and May 1998 at Avon Park
Air Force Range (APR). The presence of 87 other species ofamphibians, reptiles, and mammals
also were detected. Selected species ofbirds were noted, particularly if they were found dead on
APR roads. We recorded nine new county records ofamphibians and reptiles from Polk and
Highlands counties, based on range maps presented in Ashton and Ashton (1981, 1985, 1988).
We discuss a biogeographic model based on the vertebrates recorded from APR, the Lake Wales
Ridge, and the low dune region along SR 64 to explain some of the distributional anomalies
associated with the Bombing Range Ridge and vicinity. (199 page document
Interfacing microwave qubits and optical photons via spin ensembles
A protocol is discussed which allows one to realize a transducer for single
photons between the optical and the microwave frequency range. The transducer
is a spin ensemble, where the individual emitters possess both an optical and a
magnetic-dipole transition. Reversible frequency conversion is realized by
combining optical photon storage, by means of EIT, with the controlled
switching of the coupling between the magnetic-dipole transition and a
superconducting qubit, which is realized by means of a microwave cavity. The
efficiency is quantified by the global fidelity for transferring coherently a
qubit excitation between a single optical photon and the superconducting qubit.
We test various strategies and show that the total efficiency is essentially
limited by the optical quantum memory: It can exceed 80% for ensembles of NV
centers and approaches 99% for cold atomic ensembles, assuming state-of-the-art
experimental parameters. This protocol allows one to bridge the gap between the
optical and the microwave regime so to efficiently combine superconducting and
optical components in quantum networks
Sideband generation of transient lasing without population inversion
We suggest a method to generate coherent short pulses by generating a
frequency comb using lasing without inversion in the transient regime. We use a
universal method to study the propagation of a pulse in various spectral
regions through an active medium that is strongly driven on a low-frequency
transition on a time scale shorter than the decoherence time. The results show
gain on the sidebands at different modes can be produced even if there is no
initial population inversion prepared. Besides the production of ultra-short
pulse this frequency comb may have applications towards making short-wavelength
or Tera-hertz lasers
Early warning signal reliability varies with COVID-19 waves
Early warning signals (EWSs) aim to predict changes in complex systems from phenomenological signals in time series data. These signals have recently been shown to precede the emergence of disease outbreaks, offering hope that policymakers can make predictive rather than reactive management decisions. Here, using a novel, sequential analysis in combination with daily COVID-19 case data across 24 countries, we suggest that composite EWSs consisting of variance, autocorrelation and skewness can predict nonlinear case increases, but that the predictive ability of these tools varies between waves based upon the degree of critical slowing down present. Our work suggests that in highly monitored disease time series such as COVID-19, EWSs offer the opportunity for policymakers to improve the accuracy of urgent intervention decisions but best characterize hypothesized critical transitions
RETROCAM: A Versatile Optical Imager for Synoptic Studies
We present RETROCAM, an auxiliary CCD camera that can be rapidly inserted
into the optical beam of the MDM 2.4m telescope. The speed and ease of
reconfiguring the telescope to use the imager and a straightforward user
interface permit the camera to be used during the course of other observing
programs. This in turn encourages RETROCAM's use for a variety of monitoring
projects.Comment: 6 pages, 6 figures, Accepted by A
The role of inflammation in temporal shifts in the inflammatory bowel disease mucosal microbiome
A Comparison of Small Signal Modulation Parameter Extraction Techniques for Vertical-Cavity, Surface-Emitting Lasers
The small signal modulation characteristics of a vertical-cavity, surface-emitting laser (VCSEL) are determined using three different measurements: relative intensity noise, frequency response, and high resolution optical spectra. The resonant and damping frequencies were measured, and related rate equation parameters were extracted; excellent agreement was found both between experiment and theory, and amongst the different measurement techniques. The results and procedures are compared, and the findings are presented below
A Critical Comparison of High-Speed VCSEL Characterisation Techniques
This paper critically compares, for the first time, common microwave and optical procedures used for the high-speed characterisation of vertical-cavity, surface-emitting lasers (VCSELs). The intrinsic small-signal modulation characteristics of a VCSEL are measured, and the related rate equation parameters are extracted. Observed trends show excellent agreement with theory. The modulation characteristics of the VCSEL are determined by examining three different responses: relative intensity noise, S21 response, and high-resolution optical spectra. The various experimental techniques yielded consistent results. The relative strengths and weaknesses of each measurement are investigated below
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