Visible and near infrared observation on the Global Aerosol Backscatter Experiment (GLOBE)

The Global Aerosol Backscatter Experiment (GLOBE) was intended to provide data on prevailing values of atmospheric backscatter cross-section. The primary intent was predicting the performance of spaceborne lidar systems, most notably the Laser Atmospheric Wind Sounder (LAWS) for the Earth Observing System (EOS). The second and related goal was to understand the source and characteristics of atmospheric aerosol particles. From the GLOBE flights, extensive data was obtained on the structure of clouds and the marine planetary boundary layer. A notable result for all observations is the consistency of the large increases in the aerosol scattering ratio for the marine boundary layer. Other results are noted

Defining Success: The Politics of Evaluation in Alcohol and Drug Abuse Treatment Programs

Alcohol and drug abuse treatment programs must respond to several important stakeholders or beneficiaries of services who have an investment in how success is defined. Utilizing data from recent statewide studies of treatment outcomes of alcohol and drug abuse services, this paper concludes that a strict adherence to an abstinence-only model of success, rigidly adopted by many in the treatment industry is counterproductive. Multiple measures of success are essential to fully understand and assess a changing model of intervention in the chemical dependency field

The Invisible Histories Project: Documenting the Queer South

The Invisible Histories Project works with archives and Queer communities in Alabama, Georgia, and Mississippi to identify and collect material documenting the history of the Queer South

Modeling the spectral shape of absorption by chromophoric dissolved organic matter

A single exponential model of the form ag(λ)∝e -seλ was evaluated in the context of its application and interpretation in describing absorption by chromophoric dissolved organic matter (CDOM), ag, as a function of wavelength, λ. The spectral slope, se, is often used as a proxy for CDOM composition, including the ratio of fulvic to humic acids and molecular weight. About three-quarters of the variability in se values from the literature could be explained by the different spectral ranges used in each study. Dependency on different spectral ranges resulted from the relatively weak performance of the single exponential as a descriptor of ag(λ) in comparison to other models that allow for greater spectral curvature. Consequently, actual variability in the spectral shape of absorption, and thus the composition of CDOM, from widely varying water types appears less than currently thought. The usefulness of five other models in describing CDOM absorption spectra in the visible domain was also evaluated. Six data sets collected with an ac9 in-situ spectrophotometer from around the coastal United States were used in the analysis. All models considered performed better than the conventional single exponential model, with the exception of a double exponential model, where the second exponential term contributed little new information in the fit. Statistically, the most useful model (judged by an analysis of variance) in the visible range was a hyperbolic model of the form: a g(λ)∝λ-sh. Although the hyperbolic model was less dependent on the spectral range used in the fit, some dependency remained. The most representative model for describing ag(λ) from the six regions considered in this study, with ag at 412 nm as input, was: ag(λ)=ag(412)(λ/412) -6.92. This spectral relationship may be suitable for remote sensing semi-analytical models which must compute a spectrum from a single estimate of CDOM absorption in the blue derived from a remotely sensed water-leaving radiance signal

Vibrational-Resonance Enhancement of Positron Annihilation in Molecules

A first study of positron annihilation as a function of positron energy was performed. The rate of annihilation of low-energy positrons in molecular gases was discussed. It was shown that the large observed values of annihilation rates are due to the excitation of long-lived vibrational resonances of the positron-molecule complex. The results are consistent with a theoretical model of resonant annihilation

GParareal: A time-parallel ODE solver using Gaussian process emulation

Sequential numerical methods for integrating initial value problems (IVPs) can be prohibitively expensive when high numerical accuracy is required over the entire interval of integration. One remedy is to integrate in a parallel fashion, "predicting" the solution serially using a cheap (coarse) solver and "correcting" these values using an expensive (fine) solver that runs in parallel on a number of temporal subintervals. In this work, we propose a time-parallel algorithm (GParareal) that solves IVPs by modelling the correction term, i.e. the difference between fine and coarse solutions, using a Gaussian process emulator. This approach compares favourably with the classic parareal algorithm and we demonstrate, on a number of IVPs, that GParareal can converge in fewer iterations than parareal, leading to an increase in parallel speed-up. GParareal also manages to locate solutions to certain IVPs where parareal fails and has the additional advantage of being able to use archives of legacy solutions, e.g. solutions from prior runs of the IVP for different initial conditions, to further accelerate convergence of the method -- something that existing time-parallel methods do not do

Thirty Years Of Wetland Conservation In Montana

In 1985 the Montana Legislature authorized the Department of Fish, Wildlife and Parks (FWP) to use funds from migratory bird hunting licenses “…for the protection, conservation, and development of wetlands in Montana”, thereby creating the Migratory Bird Wetland Program (a.k.a. State Duck Stamp Program).  Wetlands and their associated uplands provide critical nesting, foraging, brood-rearing, and migration habitat for waterfowl and other wetland-associated wildlife.  Wetlands also provide critical ecosystem functions important for our communities and wildlife, including water purification, flood control, and groundwater recharge.  FWP’s Migratory Bird Wetland Program is dedicated to conserving wetlands and associated uplands to benefit Montana’s wildlife, especially migratory birds, to enhance consumptive and non-consumptive recreational opportunities, and to maintain wetland systems for Montana’s citizens.  Since many of the opportunities were on private land, it was essential for FWP personnel to learn how best to work with farmers and ranchers to benefit their operations as well as wildlife and wetland values.  In addition to the partnership of private landowners, many other agencies and organizations have been partners in habitat projects.  The program has adapted to changing opportunities and conservation needs over time.  We will chronicle the past 30 years of program implementation, showcase successes, and discuss a philosophy for continued wetland conservation into the future

Nano-porosity in GaSb induced by swift heavy ion irradiation

Nano-porous structures form in GaSb after ion irradiation with 185 MeV Au ions. The porous layer formation is governed by the dominant electronic energy loss at this energy regime. The porous layer morphology differs significantly from that previously reported for low-energy, ion-irradiated GaSb. Prior to the onset of porosity, positron annihilation lifetime spectroscopy indicates the formation of small vacancy clusters in single ion impacts, while transmission electron microscopy reveals fragmentation of the GaSb into nanocrystallites embedded in an amorphous matrix. Following this fragmentation process, macroscopic porosity forms, presumably within the amorphous phase.The authors thank the Australian Research Council for support and the staff at the ANU Heavy Ion Accelerator Facility for their continued technical assistance. R.C.E. acknowledges the support from the Office of Basic Energy Sciences of the U.S. DOE (Grant No. DE-FG02-97ER45656)

Microscale Quantification of the Absorption by Dissolved and Particulate Material in Coastal Waters with an ac-9

Measuring coastal and oceanic absorption coefficients of dissolved and particulate matter in the visible domain usually requires a methodology for amplifying the natural signal because conventional spectrophotometers lack the necessary sensitivity. The WET Labs ac-9 is a recently developed in situ absorption and attenuation meter with a precision better than ±0.001 m−1 in the raw signal, which is sufficient to make these measurements in pristine samples. Whereas the superior sensitivity of the ac-9 has been well documented, the accuracy of in situ measurements for bio-optical applications has not been rigorously evaluated. Obtaining accurate results with an ac-9 requires careful attention to calibration procedures because baselines drift as a result of the changing optical properties of several ac-9 components. To correct in situ measurements for instrument drift, a pressurized flow procedure was developed for calibrating an ac-9 with optically clean water. In situ, micro- (cm) to fine- (m) scale vertical profiles of spectral total absorption, at(λ), and spectral absorption of dissolved materials, ag(λ), were then measured concurrently using multiple meters, corrected for drift, temperature, salinity, and scattering errors and subsequently compared. Particulate absorption, ap(λ), was obtained from at(λ) − ag(λ). CTD microstructure was simultaneously recorded. Vertical profiles of ag(λ), at(λ), and ap(λ) were replicated with different meters within ±0.005 m−1, and spectral relationships compared well with laboratory measurements and hydrographic structure