4,883 research outputs found
Use Permits: A Hedonistic Approach Applied to Farmland in the Southeastern US
In the State of Georgia, any agricultural producer who wishes to pump more than 100,000 gallons of water a day for crop irrigation is required to have an irrigation permit. The permit stays with the land and in the event of sale the permit is transferred with the property. Until recently, permits were essentially granted freely to all applicants in the Flint River water basin, without limit. In 1999, however, with increasing demand for water from growing urban Atlanta and several years of drought in the Southeast, the state of Georgia placed a moratorium on the issuance of agricultural water permits in the Flint River basin. This research exploits this policy change within a hedonic pricing framework to estimate the value of irrigation rights in the Southeast US. While the value of irrigation rights has been studied extensively in the western US, differences in property rights and legal regimes, as well as a lack of established water-rights markets in the East, leave us with little information regarding the value of irrigation rights in this setting. Working Paper 06-4
Mechanisms of Organic Matter Preservation in Continental Margin Sediments from the Gulf of Maine
Burial of organic carbon on marine shelves is an important process in the long-term sequestration of carbon from the marine carbon cycle. As organic matter in marine environments is consumed and resuspended by microorganisms, only a small portion is preserved. This organic material is preferentially associated with the fine-grained fraction of continental margin sediments. The strong correlation between organic matter content and fine-grained particles has led to speculation that organic matter may be adsorbed onto mineral surface and physically protected by incorporation into aggregates.
Two methods were used to determine the role of aggregates in the physical preservation of organic carbon in marine sediments from the Gulf of Maine. First, carbon storage potential was measured through a range of particle and aggregate sizes. Silt-size (2-53 ÎĽm) and clay-size (\u3c2 \u3eÎĽm) fractions were isolated using settling columns, and separated by density into particles (p\u3e2.3 g cm-1) and aggregates (p-1) using heavy liquid floatation. Systematic differences between preserved carbon content in silt and clay particle and aggregate fractions were determined by measuring organic carbon and specific surface area via a carbon analyzer and the nitrogen gas adsorption method. Second, differences in physical stability between silt and clay aggregates were measured. Relative size distributions of silt and clay aggregates were measured, via flow cytometry and x-ray disc centrifugation, before and after exposure to stepwise increasing levels of sonic energy.
The highest levels of organic carbon were associated with clay-sized aggregates, but aggregates in the silt-size fraction around 3 cm below the sediment water interface appear to be the most physically stable. This suggests that although organic carbon is preferentially associated with aggregates, it may not be the sole mechanism controlling aggregate physical stability. Increased aggregate stability could be the result of physical process such as compaction, dewatering, lithification, and/or the quality of organic carbon beginning to occur around 3 cm of depth
Artificial Light at Night (ALAN): An Anthropogenic Challenge for Urban Lizard Behavior and Physiology
Artificial light at night (ALAN) is a byproduct of anthropogenic illumination that disrupts the behaviors and physiologies of organisms as diverse as mammals, birds, non-avian reptiles, fishes, and insects. In a time of increasing urbanization, discovering the impacts of ALAN on urban organisms is crucial to conservation efforts. In this study, we investigated the impacts of ALAN on the behaviors and physiology of the green anole lizard (Anolis carolinensis). Two groups of 24 urban wild-caught adult green anoles (12 males, 12 females per group) were exposed to two different light-dark cycles in a controlled lab setting for six weeks. One group was exposed to a light-dark cycle that simulated the natural light-dark cycle of a summer day in San Antonio, Texas, and the other group was exposed, in addition to the natural light-dark cycle, to an ALAN source that simulated the light intensity of the streetlights on an urban university campus. After an acclimation period, we conducted a series of behavioral trials. Three trials were repeated during mid-day and mid-night: open field tests, to examine exploratory behavior; foraging trials, to examine prey consumption; and conspecific trials, to examine same-sex interactions. The fourth trial examined behavioral time allocation over two 24 h periods. At the conclusion of behavioral trials, we measured each lizard’s body mass and snout-vent length (SVL) and the mass of its abdominal fat pads, liver, and reproductive tissues. Our data demonstrate that lizards exposed to ALAN were more likely to be awake at night. While they were awake, lizards exposed to ALAN used the light to explore, forage, and display to conspecifics. However, during the day, lizards exposed to ALAN were more likely to be asleep, were slower to move and forage, and females displayed less frequently than females not exposed to ALAN. Lizards exposed to ALAN had heavier fat pads and males had heavier testes, but ALAN did not impact liver mass, overall body mass, or female reproductive tissue mass. In sum, ALAN appears to cause behavioral trade-offs between diurnal and nocturnal activity and alters metabolic and reproductive processes within green anoles. These behavioral and physiological changes could cause the lizards to be exposed to novel situations and impact higher-level organization within the urban environment
The relationship between shame and leave-taking behavior duration of violent relationship social support -seeking attributions emotional abuse sexual assault and PTSD symptoms in battered women
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CO2 reduction with protons and electrons at a boron-based reaction center.
Borohydrides are widely used reducing agents in chemical synthesis and have emerging energy applications as hydrogen storage materials and reagents for the reduction of CO2. Unfortunately, the high energy cost associated with the multistep preparation of borohydrides starting from alkali metals precludes large scale implementation of these latter uses. One potential solution to this issue is the direct synthesis of borohydrides from the protonation of reduced boron compounds. We herein report reactions of the redox series [Au(B2P2)] n (n = +1, 0, -1) (B2P2, 9,10-bis(2-(diisopropylphosphino)phenyl)-9,10-dihydroboranthrene) and their conversion into corresponding mono- and diborohydride complexes. Crucially, the monoborohydride can be accessed via protonation of [Au(B2P2)]-, a masked borane dianion equivalent accessible at relatively mild potentials (-2.05 V vs. Fc/Fc+). This species reduces CO2 to produce the corresponding formate complex. Cleavage of the formate complex can be achieved by reduction (ca. -1.7 V vs. Fc/Fc+) or by the addition of electrophiles including H+. Additionally, direct reaction of [Au(B2P2)]- with CO2 results in reductive disproportion to release CO and generate a carbonate complex. Together, these reactions constitute a synthetic cycle for CO2 reduction at a boron-based reaction center that proceeds through a B-H unit generated via protonation of a reduced borane with weak organic acids
Case Study of Zero Waste Bag Design Utilizing Pre-Consumer Upholstery Fabric Waste
The upholstery industry generates tremendous fabric waste each year, which negatively impacts the environment. The researchers aimed to explore a potential use of pre-consumer upholstery fabric waste through the creation of reusable grocery bags, under the frame of Barquet et al.\u27s (2016) five sustainability factors for product service system business model. By utilizing 98.88% of 234.48 ounces of upholstery fabric waste provided by an upholsterer, this study resulted in the creation of 30 reusable grocery bags with a total estimated retail value of $1,300. We revealed the positive linkage of our reusable bag design process to four of the sustainability factors: Apply Designs for Environment, Identify Economic Value, Promote Behavior Change, and Act Towards Social Well-being. Findings also suggest this upholstery fabric waste should no longer be considered waste, as it performs as valuable resources for the creation of other durable products
Chemotropic guidance facilitates axonal regeneration and synapse formation after spinal cord injury.
A principal objective of spinal cord injury (SCI) research is the restoration of axonal connectivity to denervated targets. We tested the hypothesis that chemotropic mechanisms would guide regenerating spinal cord axons to appropriate brainstem targets. We subjected rats to cervical level 1 (C1) lesions and combinatorial treatments to elicit axonal bridging into and beyond lesion sites. Lentiviral vectors expressing neurotrophin-3 (NT-3) were then injected into an appropriate brainstem target, the nucleus gracilis, and an inappropriate target, the reticular formation. NT-3 expression in the correct target led to reinnervation of the nucleus gracilis in a dose-related fashion, whereas NT-3 expression in the reticular formation led to mistargeting of regenerating axons. Axons regenerating into the nucleus gracilis formed axodendritic synapses containing rounded vesicles, reflective of pre-injury synaptic architecture. Thus, we report for the first time, to the best of our knowledge, the reinnervation of brainstem targets after SCI and an essential role for chemotropic axon guidance in target selection
Assaying protein palmitoylation in plants
<p>Abstract</p> <p>Background</p> <p>Protein S-acylation (also known as palmitoylation) is the reversible post-translational addition of acyl lipids to cysteine residues in proteins through a thioester bond. It allows strong association with membranes. Whilst prediction methods for S-acylation exist, prediction is imperfect. Existing protocols for demonstrating the S-acylation of plant proteins are either laborious and time consuming or expensive.</p> <p>Results</p> <p>We describe a biotin switch method for assaying the S-acylation of plant proteins. We demonstrate the technique by showing that the heterotrimeric G protein subunit AGG2 is S-acylated as predicted by mutagenesis experiments. We also show that a proportion of the Arabidopsis alpha-tubulin subunit pool is S-acylated <it>in planta</it>. This may account for the observed membrane association of plant microtubules. As alpha-tubulins are ubiquitously expressed they can potentially be used as a positive control for the S-acylation assay regardless of the cell type under study.</p> <p>Conclusion</p> <p>We provide a robust biotin switch protocol that allows the rapid assay of protein S-acylation state in plants, using standard laboratory techniques and without the need for expensive or specialised equipment. We propose alpha-tubulin as a useful positive control for the protocol.</p
Sulfite Residues in Maraschino Cherries
A survey of 53 samples of maraschino cherries from 14 different processors revealed that total sulfite residues averaged 52.3 ± 44.7 ppm. However, 58.5% of the samples had less than 40 ppm total SO2, while only 7.6% had greater than 120 ppm total SO2 indicating that the distribution was skewed in the direction of lower residue levels. Free sulfite residues in the 53 samples were considerably lower, averaging 14.2 ± 7.1 ppm. With free SO2 levels, 35.8% of the samples had less than 10 ppm free SO2, while only 5.7% had greater than 30 ppm free SO2. With an average serving size of one cherry (3–7 g), maraschino cherries would contribute only 0.16–0.37 mg per serving of total sulfites as SO2
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