739 research outputs found
Economic Impact of Withdrawing Specific Agricultural Pesticides in the Lower Rio Grande Valley
The Air, Pesticides, and Toxics Division of the Environmental Protection Agency (EPA) has encouraged all states to develop a plan to manage the use of pesticides to prevent application that would result in unreasonable risks to human health and the environment from contamination of ground water. In February, 1988, EPA proposed a strategy where by they would regulate certain pesticides by prohibiting their use in areas vulnerable to leaching unless a state develops and implements a management plan acceptable to EPA. However, banning the use of a pesticide in a region is the worst case scenario available to the TWC for managing water quality.
The Texas Water Commission (TWC) assessed the State for areas vulnerable to leaching and found the Lower Rio Grande Valley (LRGV) to be a highly vulnerable area. This study examines three pesticides (atrazine, dicrotophos, and aldicarb) currently used in the LRGV that were identified by the TWC as potential contaminants of ground water. Alternative methods of controlling pests in this region were identified, and the economic impacts of withdrawing one or all three of these pesticides from the study area were estimated.
Regional impacts on gross receipts (sales), variable costs, and net returns were determined. If atrazine use were banned in the LRGV, corn and sorghum sales would decrease by approximately 2 million dollars, leaving farmers in the region with a 600,000 for the region as a whole. Banning aldicarb use in the study area would reduce citrus sales by almost 200,000, and reduce farmer net income by over $3 million annually
A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies
We described a versatile spectrometer designed for the study of dynamic nuclear polarization (DNP) at low temperatures and high fields. The instrument functions both as an NMR spectrometer operating at 212 MHz ([superscript 1]H frequency) with DNP capabilities, and as a pulsed-EPR operating at 140 GHz. A coiled TE[subscript 011] resonator acts as both an NMR coil and microwave resonator, and a double balanced ([superscript 1]H, [superscript 13]C) radio frequency circuit greatly stabilizes the NMR performance. A new 140 GHz microwave bridge has also been developed, which utilizes a four-phase network and ELDOR channel at 8.75 GHz, that is then multiplied and mixed to obtain 140 GHz microwave pulses with an output power of 120 mW. Nutation frequencies obtained are as follows: 6 MHz on S = 1/2 electron spins, 100 kHz on [superscript 1]H, and 50 kHz on [superscript 13]C. We demonstrate basic EPR, ELDOR, ENDOR, and DNP experiments here. Our solid effect DNP results demonstrate an enhancement of 144 and sensitivity gain of 310 using OX063 trityl at 80 K and an enhancement of 157 and maximum sensitivity gain of 234 using Gd-DOTA at 20 K, which is significantly better performance than previously reported at high fields (⩾3 T).National Institutes of Health (U.S.) (EB002804)National Institutes of Health (U.S.) (EB002026)National Institutes of Health (U.S.) (EB001965)National Institutes of Health (U.S.) (EB004866)Deutsche Forschungsgemeinschaft (Postdoctoral Fellowship
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Collaborative Autoethnographic Writing as Communal Curative
This collaborative autoethnography reflects on how each author experienced COVID-19 and associated precarity. We explore the ways in which this experience relates to our identities (both particular and plural), and our positionalities in terms of privilege and marginality. As a collective of diverse collaborators, we confront dialectical questions of self and society. Our contributions reveal our advantage/disadvantage, mobility/immobility, and the borders and boundedness before/during/after COVID-19. We show the power of curative writing in collaborative autoethnography and how the sharing of our experiences of vulnerability represents an invitation to human connection
The relationship between early life stress and microstructural integrity of the corpus callosum in a non-clinical population
United Kingdo
Atypical Epstein-Barr Viral Genomic Structure in Lymphoma Tissue and Lymphoid Cell Lines
Epstein-Barr virus (EBV) DNA is found within the malignant cells of some subtypes of lymphoma, and viral presence is being exploited for improved diagnosis, monitoring, and management of affected patients. Recent work suggests that viral genomic polymorphism, such as partial deletion of the viral genome, could interfere with virus detection in tumor tissues. To test for atypical forms of the EBV genome, 98 lymphomas and 6 infected cell lines were studied using a battery of 6 quantitative polymerase chain reaction assays targeting disparate sections of EBV DNA. Fifty of the lymphomas (51%) had no amplifiable EBV DNA, and 38 lymphomas (39%) had low-level EBV infection that was deemed incidental based on EBV-encoded RNA (EBER) in situ hybridization results. The remaining 10 lymphomas (10%) had high EBV loads and EBER localization to malignant cells by EBER in situ hybridization. All 10 represented lymphoma subtypes were previously associated with EBV (Burkitt, diffuse large B-cell, or T-cell type), whereas no remnants of EBV were detected in other lymphoma subtypes (follicular, small lymphocytic, mantle cell, or marginal zone type). Interestingly, 4 of the 10 infected lymphomas had evidence of atypical viral genomes, including 3 of 4 infected T-cell lymphomas with aberrant loss of LMP2 amplicons, and a single diffuse large B-cell lymphoma lacking the central part of the viral genome spanning BamH1W, BZLF1, and EBNA1 gene segments. A reasonable screening strategy for infected malignancy involves applying EBER1 and LMP1 quantitative polymerase chain reaction assays and confirming that values exceeding 2000 copies of EBV per 100,000 cells have EBER localization to malignant cells
Economic Impact of Withdrawing Specific Agricultural Pesticides in the Lower Rio Grande Valley
The Air, Pesticides, and Toxics Division of the Environmental Protection Agency (EPA) has encouraged all states to develop a plan to manage the use of pesticides to prevent application that would result in unreasonable risks to human health and the environment from contamination of ground water. In February, 1988, EPA proposed a strategy where by they would regulate certain pesticides by prohibiting their use in areas vulnerable to leaching unless a state develops and implements a management plan acceptable to EPA. However, banning the use of a pesticide in a region is the worst case scenario available to the TWC for managing water quality.
The Texas Water Commission (TWC) assessed the State for areas vulnerable to leaching and found the Lower Rio Grande Valley (LRGV) to be a highly vulnerable area. This study examines three pesticides (atrazine, dicrotophos, and aldicarb) currently used in the LRGV that were identified by the TWC as potential contaminants of ground water. Alternative methods of controlling pests in this region were identified, and the economic impacts of withdrawing one or all three of these pesticides from the study area were estimated.
Regional impacts on gross receipts (sales), variable costs, and net returns were determined. If atrazine use were banned in the LRGV, corn and sorghum sales would decrease by approximately 2 million dollars, leaving farmers in the region with a 600,000 for the region as a whole. Banning aldicarb use in the study area would reduce citrus sales by almost 200,000, and reduce farmer net income by over $3 million annually
Cryogenic sample exchange NMR probe for magic angle spinning dynamic nuclear polarization
We describe a cryogenic sample exchange system that dramatically improves the efficiency of magic angle spinning (MAS) dynamic nuclear polarization (DNP) experiments by reducing the time required to change samples and by improving long-term instrument stability. Changing samples in conventional cryogenic MAS DNP/NMR experiments involves warming the probe to room temperature, detaching all cryogenic, RF, and microwave connections, removing the probe from the magnet, replacing the sample, and reversing all the previous steps, with the entire cycle requiring a few hours. The sample exchange system described here—which relies on an eject pipe attached to the front of the MAS stator and a vacuum jacketed dewar with a bellowed hole—circumvents these procedures. To demonstrate the excellent sensitivity, resolution, and stability achieved with this quadruple resonance sample exchange probe, we have performed high precision distance measurements on the active site of the membrane protein bacteriorhodopsin. We also include a spectrum of the tripeptide N-f-MLF-OH at 100 K which shows 30 Hz linewidths.National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant EB-002804)National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant EB-001960)National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant EB-001035)National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant EB-002026)National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant EB-003151)National Science Foundation (U.S.). Graduate Research Fellowship Progra
Re-examination of the Controversial Coexistence of Traumatic Brain Injury and Posttraumatic Stress Disorder: Misdiagnosis and Self-Report Measures
The coexistence of traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) remains a controversial issue in the literature. To address this controversy, we focused primarily on the civilian-related literature of TBI and PTSD. Some investigators have argued that individuals who had been rendered unconscious or suffered amnesia due to a TBI are unable to develop PTSD because they would be unable to consciously experience the symptoms of fear, helplessness, and horror associated with the development of PTSD. Other investigators have reported that individuals who sustain TBI, regardless of its severity, can develop PTSD even in the context of prolonged unconsciousness. A careful review of the methodologies employed in these studies reveals that investigators who relied on clinical interviews of TBI patients to diagnose PTSD found little or no evidence of PTSD. In contrast, investigators who relied on PTSD questionnaires to diagnose PTSD found considerable evidence of PTSD. Further analysis revealed that many of the TBI patients who were initially diagnosed with PTSD according to self-report questionnaires did not meet the diagnostic criteria for PTSD upon completion of a clinical interview. In particular, patients with severe TBI were often misdiagnosed with PTSD. A number of investigators found that many of the severe TBI patients failed to follow the questionnaire instructions and erroneously endorsed PTSD symptoms because of their cognitive difficulties. Because PTSD questionnaires are not designed to discriminate between PTSD and TBI symptoms or determine whether a patient's responses are accurate or exaggerated, studies that rely on self-report questionnaires to evaluate PTSD in TBI patients are at risk of misdiagnosing PTSD. Further research should evaluate the degree to which misdiagnosis of PTSD occurs in individuals who have sustained mild TBI
Search for CP Violation in the Decay Z -> b (b bar) g
About three million hadronic decays of the Z collected by ALEPH in the years
1991-1994 are used to search for anomalous CP violation beyond the Standard
Model in the decay Z -> b \bar{b} g. The study is performed by analyzing
angular correlations between the two quarks and the gluon in three-jet events
and by measuring the differential two-jet rate. No signal of CP violation is
found. For the combinations of anomalous CP violating couplings, and , limits of \hat{h}_b < 0.59h^{\ast}_{b} < 3.02$ are given at 95\% CL.Comment: 8 pages, 1 postscript figure, uses here.sty, epsfig.st
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