299 research outputs found
QUANTIFYING HYDRAULIC CONDUCTIVITY IN MINE DRAINAGE PASSIVE TREATMENT SYSTEM VERTICAL FLOW BIOREACTORS
Heavy industrial mining has occurred in the United States for more than 100 years, and in many cases, has led to large-scale environmental degradation, especially from historical operations where mining occurred prior to environmental regulations. Many of these derelict or abandoned operations discharge abandoned mine drainage (AMD), which contains ecotoxic metal-contamination that impairs receiving stream water quality and negatively impacts local ecology. Passive treatment systems (PTS) are cost effective treatment technologies that are designed to use relatively little fossil fuels and natural physicochemical (e.g., limestone dissolution) and biological (e.g., bacterial sulfate reduction) processes for the treatment of AMD.
One of the key components of PTS are vertical flow bioreactors (VFBRs). VFBRs typically include waste organic materials as microbial substrates overlying rock drainage layers. They utilize the dissolution of limestone to generate alkalinity for neutralization of excess protons and promote sulfate-reducing bacteria for additional alkalinity generation and trace metal removal as sulfides. However, long-term operation and maintenance issues in PTS include decreased hydraulic conductivity in VFBRs. Decreased hydraulic conductivity leads to either water by-passing the cell or decreased treatment efficiencies. This research focused on quantifying the hydraulic conductivity and characterizing the organic layer in VFBRs of multiple passive treatment systems with the intention of developing plans for extending the lives of the treatment systems.
VFBRs at the Mayer Ranch, Hartshorne and Red Oak PTS were selected for this study. This research used four different methods to estimate hydraulic conductivity in VFBRs that have been in operation for 8-15 years. Hydraulic conductivity was compared against several different treatment media characteristics. The hydraulic conductivity measurements ranged from 9.93x10-3 to 1.74x10-5 cm/s. The comparison of the hydraulic conductivity and the treatment media characteristics indicated a trend that as particle density increased the hydraulic conductivity decreased. The comparison of the different methods did not yield one definitive method, but found that site variables dictated that certain methods may be more accurate or viable than others. The results helped to characterize the treatment media and quantified the hydraulic conductivity of the treatment media of VFBRs
Using Commodity Graphics Hardware for Real-Time Digital Hologram View-Reconstruction
View-reconstruction and display is an important part of many applications in digital holography such as computer vision and microscopy. Thus far, this has been an offline procedure for megapixel sized holograms. This paper introduces an implementation of real-time view-reconstruction using programmable graphics hardware. The theory of Fresnel-based view-reconstruction is introduced, after which an implementation using stream programming is presented. Two different fast Fourier transform (FFT)-based reconstruction methods are implemented, as well as two different FFT strategies. The efficiency of the methods is evaluated and compared to a CPU-based implementation, providing over 100 times speedup for a hologram size of 2048 x 2048
Using Commodity Graphics Hardware for Real-Time Digital Hologram View-Reconstruction
View-reconstruction and display is an important part of many applications in digital holography such as computer vision and microscopy. Thus far, this has been an offline procedure for megapixel sized holograms. This paper introduces an implementation of real-time view-reconstruction using programmable graphics hardware. The theory of Fresnel-based view-reconstruction is introduced, after which an implementation using stream programming is presented. Two different fast Fourier transform (FFT)-based reconstruction methods are implemented, as well as two different FFT strategies. The efficiency of the methods is evaluated and compared to a CPU-based implementation, providing over 100 times speedup for a hologram size of 2048 x 2048
Heroin Use and Sex: Some Patterns in Miami-Dade County, Florida
Much of the literature on heroin and opioid addiction holds that regular, long-term users of heroin and other opioids lose interest in sex as their drug using careers lengthen. Analysis of self-reports collected from IDUs in two cross- sectional surveys on patterns of risk behavior in Miami-Dade County, Florida, reveals that large proportions of IDUs report using heroin before or during sex across a wide range of self-injection experience, from as little as twelve months to over 40 years. One half or more of respondents to both surveys reported using heroin in their recent sexual experiences, with similar proportions reported by both males and females. The same IDUs, however, tend not to report using prescription painkillers before or during sex. This finding indicates that co-occurring risk behavior related to both sexual behavior and heroin use may be more prevalent among long-term IDUs than previous literature has suggested
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Compliance to Bleach Disinfection Protocols among Injecting Drug Users in Miami
Bleach cleansing of injection equipment has been recommended to reduce the risk of human immunodeficiency virus (HIV) transmission associated with the reuse of injection equipment by injecting drug users (IDUs). We evaluated the recall and performance of the most commonly recommended bleach cleansing procedure of two complete fillings of the syringe with bleach, followed by two complete fillings with rinse water, and not putting used bleach and water back into source containers. IDUs were taught this procedure on enrollment in an HIV prevention demonstration project in Dade County, Florida. During follow-up session 6-12 months after initial training, the knowledge and ability of IDUs to perform bleach cleansing were assessed by trained observers using a standardized method. In 1988-90, we assessed the knowledge and ability of 450 IDUs to perform the bleach cleansing procedure taught at enrollment. More than 90% of IDUs assessed performed the basic steps. However, only 43.1% completely filled the syringe with bleach and only 35.8% completely filled the syringe with bleach at least twice. Substantial proportions of IDUs did not perform all the steps of the previously taught bleach cleansing procedure. Compliance decreased as the number of steps required was increased. This limited compliance may make bleach cleansing less effective and suggests that some IDUs may fail to adequately disinfect injection equipment and therefore sterile needles and syringes are safer than bleach-cleansed ones. Compliance testing can help assess the effectiveness of HIV prevention programs. © 1994 Raven Press, Ltd., New York
Self-interest And Public Interest: The Motivations Of Political Actors
Self-Interest and Public Interest in Western Politics showed that the public, politicians, and bureaucrats are often public spirited. But this does not invalidate public-choice theory. Public-choice theory is an ideal type, not a claim that self-interest explains all political behavior. Instead, public-choice theory is useful in creating rules and institutions that guard against the worst case, which would be universal self-interestedness in politics. In contrast, the public-interest hypothesis is neither a comprehensive explanation of political behavior nor a sound basis for institutional design
Enhancing the health of women living with HIV: the SMART/EST Women’s Project
The principal objective of these multisite studies (Florida, New York, New Jersey: epicenters for human immunodeficiency virus [HIV] among women) was to develop and implement effective combinations of behavioral interventions to optimize the health status of the most neglected and understudied population affected by the acquired immunodeficiency syndrome (AIDS) epidemic in the United States: poor women of color living with HIV. The two studies enrolled nearly 900 women randomly assigned to “high intensity” (cognitive–behavioral stress management training combined with expressive–supportive therapy [CBSM]+ group) or “low intensity” (individual psychoeducational program) treatment conditions over a period of 9 years. The initial study of the stress management and relaxation training/expressive–supportive therapy (SMART/EST) Women’s Project (SWP I) focused on reducing depression and anxiety, as well as improving self-efficacy and overall quality of life for women with case-defined AIDS. Findings from this study demonstrated the utility of CBSM+ in reducing distress (depression, anxiety) and denial, while improving social support, self-efficacy, coping skills, and quality of life. The second study (SWP II), which included all women living with HIV, extended these findings by demonstrating that exposure to CBSM+ significantly improved the ability of the participants to take advantage of a health behavior change program encouraging the adoption and maintenance of healthier lifestyle behaviors (high levels of medication adherence, appropriate nutritional intake and physical activity, safer sexual practices, and reduced alcohol use/abuse) essential for optimal health in the context of living with HIV. SWP II also determined that the intervention program was equally beneficial to less-acculturated segments of the affected population (ie, non-English speaking HIV+ women) through the creation of culturally and linguistically sensitive Spanish and Creole versions of the program. A third study (SWP III) is currently underway to “translate” this evidence-based treatment program into Community Health Centers in Miami, New York City, and metropolitan New Jersey
Fishery management plan series
Management plan discussing the three shrimp species found in the Gulf of Mexico and how to best utilize these resources for Texas
Foreground simulations for the LOFAR - Epoch of Reionization Experiment
Future high redshift 21-cm experiments will suffer from a high degree of
contamination, due both to astrophysical foregrounds and to non-astrophysical
and instrumental effects. In order to reliably extract the cosmological signal
from the observed data, it is essential to understand very well all data
components and their influence on the extracted signal. Here we present
simulated astrophysical foregrounds datacubes and discuss their possible
statistical effects on the data. The foreground maps are produced assuming 5
deg x 5 deg windows that match those expected to be observed by the LOFAR
Epoch-of-Reionization (EoR) key science project. We show that with the expected
LOFAR-EoR sky and receiver noise levels, which amount to ~52 mK at 150 MHz
after 300 hours of total observing time, a simple polynomial fit allows a
statistical reconstruction of the signal. We also show that the polynomial
fitting will work for maps with realistic yet idealised instrument response,
i.e., a response that includes only a uniform uv coverage as a function of
frequency and ignores many other uncertainties. Polarized galactic synchrotron
maps that include internal polarization and a number of Faraday screens along
the line of sight are also simulated. The importance of these stems from the
fact that the LOFAR instrument, in common with all current interferometric EoR
experiments has an instrumentally polarized response.Comment: 18 figures, 3 tables, accepted to be published in MNRA
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