2,791 research outputs found

    Predicted Limnology of the Proposed Ridges Basin Reservoir

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    A limnological evaluation was conducted for the offstream Ridges Basin Reservoir proposed by the Bureau of Reclamation in southwest Colorado. The study required the determination of existing water quality in the source river and use of the information to predict the algal standing crop, hypolimnetic oxygen deficity, Secchi disk transparency, and retention of metals in the proposed reservoir. A water quality study was conducted between May 1977 and August 1978. Samplse were collected from the Animas River, which will provide the inflow to the proposed reservoir, and from the La Plata River, which will receive discharge from the reservoir. Samples were analyzed for 49 water quality constituents. The data were used to evaluate the quality of water in both rivers with respect to the proposed Colorado Water Quatiy Standards for raw ater supply, agricultural use, and the protection of the aquatic biota. A phophorus loading model was evaluated and used to predict the summer standing crop of chlorophyl

    Disproportionality as a Framework to Target Pollution Reduction from Urban Landscapes

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    New federal water quality regulations regarding impaired waters and urban stormwater alongside a growing need to reverse eutrophication of urban lakes are creating demand to decrease nutrient export from urban landscapes, particularly lawns. We propose that Nowak’s disproportionality framework could be used to target specific households likely to generate disproportionate levels of nutrient export. The biophysical dimension would be based on landscape vulnerability (slope; soil type; proximity to lakes); the social dimension would target “inappropriate” lawn management behaviors leading to high nutrient export on these vulnerable landscapes. Understanding of lawn nutrient cycling (biophysical dimension) and homeowner beliefs and attitudes (social dimension) would be used to develop targeted, specific messages for homeowners with inappropriate management practices. A lawn management program developed with this disproportionality framework would probably be very effective, highly economical and fair, targeting only homeowners who are creating a disproportionate impact

    Total Value of Phosphorus Recovery

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    Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies

    Ultraluminous infrared galaxies: mergers of sub-L* galaxies?

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    A sample of 27 low-redshift, mostly cool, ultraluminous infrared galaxies (ULIRGs) has been imaged at 1.6 ÎŒm with the Hubble Space Telescope (HST) Near-Infrared Camera and Multi-Object Spectrometer (NICMOS). The majority (67%) of the sample's galaxies are multiple-nucleus galaxies with projected separations of up to 17 kpc, and the rest of the sample (33%) are single-nucleus galaxies, as determined by the NICMOS angular resolution limit. The average observed, integrated (host+nucleus) H magnitude of our HST H sample ULIRGs is -24.3, slightly above that of an L* galaxy (MH = -24.2), and 52% of the sample's galaxies have sub-L* luminosities. The ULIRGs in the HST H sample are not generated as a result of the merging of two luminous (i.e., ≄L*) spiral galaxies. Instead, the interactions and mergers occur in general between two, or in some cases more, less massive sub-L* (0.3-0.5L*) galaxies. Only one out of the 49 nuclei identified in the entire HST H sample has the properties of a bright quasar-like nucleus. On average, the brightest nuclei in the HST H sample galaxies (i.e., cool ULIRGs) are 1.2 mag fainter than warm ULIRGs and low-luminosity Bright Quasar Survey quasars (BQS QSOs) and 2.6 mag fainter than high-luminosity BQS QSOs. Since the progenitor galaxies involved in the merger are sub-L* galaxies, the mass of the central black hole in these ULIRGs would be only about (1-2) × 107 M☉, if the bulge-to-black hole mass ratio of nearby galaxies holds for ULIRGs. The estimated mass of the central black hole is similar to that of nearby Seyfert 2 galaxies but at least 1 order of magnitude lower than the massive black holes thought to be located at the center of high-luminosity QSOs. Massive nuclear starbursts with constant star formation rates of 10-40 M☉ yr-1 could contribute significantly to the nuclear H-band flux and are consistent with the observed nuclear H-band magnitudes of the ULIRGs in the HST H sample. An evolutionary merging scenario is proposed for the generation of the different types of ULIRGs and QSOs on the basis of the masses of the progenitors involved in the merging process. According to this scenario, cool ULIRGs would be the end product of the merging of two or more low-mass (0.3L*-0.5L*) disk galaxies. Warm ULIRGs and low-luminosity QSOs would be generated by a merger involving intermediate-mass (0.5 L*) disk galaxies. Under this scenario, warm ULIRGs could still be the dust-enshrouded phases of UV-bright low-luminosity QSOs, but cool ULIRGs, which are most ULIRGs, would not evolve into QSOs

    Lyapunov exponent and natural invariant density determination of chaotic maps: An iterative maximum entropy ansatz

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    We apply the maximum entropy principle to construct the natural invariant density and Lyapunov exponent of one-dimensional chaotic maps. Using a novel function reconstruction technique that is based on the solution of Hausdorff moment problem via maximizing Shannon entropy, we estimate the invariant density and the Lyapunov exponent of nonlinear maps in one-dimension from a knowledge of finite number of moments. The accuracy and the stability of the algorithm are illustrated by comparing our results to a number of nonlinear maps for which the exact analytical results are available. Furthermore, we also consider a very complex example for which no exact analytical result for invariant density is available. A comparison of our results to those available in the literature is also discussed.Comment: 16 pages including 6 figure

    Minimally invasive biomarkers to detect maternal physiological status in sow saliva and milk

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    In this study, we aimed to validate existing plasma assays to measure biomarkers for maternal signalling in milk and saliva of lactating sows. These biological samples are minimally invasive to the animal and could give a physiological profile of maternal qualities available to their piglets. Sows were farrowed in a zero-confinement system, and their colostrum and milk samples were manually collected during naturally occurring let-downs (i.e. not induced) over the lactation period. Saliva sampling involved sows voluntarily accepting cotton buds to chew without restraint. Commercial kits designed for blood plasma were tested, and any modifications and results are given. We successfully measured total protein, cortisol, tumour necrosis factor-α (TNF-α) and oxytocin in pig milk and saliva and immunoglobulin G (IgG) in pig milk samples. We were unsuccessful at measuring relaxin and serotonin in these biological samples. We observed higher levels of biomarkers in milk than in saliva. The measurement of TNF-α in pig milk for the first time revealed increased levels with larger litters. This development will allow more detailed understanding of biomarkers in milk. There was also evidence that the minimally invasive technique of using saliva sampling did not interrupt natural oxytocin production around parturition

    The Somali chilled meat value chain: Structure, operation, profitability and opportunities to improve the competitiveness of Somalia’s chilled meat export trade

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    Export-oriented pastoral livestock production is an important source of livelihood of the Somali people. The country is largely food deficient, with imports forming a significant proportion of basic food requirements and which are largely financed through earnings from exports of live animals and meat. The export of meat products offers more avenues for increased earnings and tax revenue by exploiting the available opportunities for domestic value addition, than does live animal trade. This study characterizes the Somali chilled export meat value chain in terms of actors, institutions and practices, and provides an initial analysis of their profitability in handling four species of livestock. It also canvasses actors’ views on opportunities and constraints faced. Its main objective is to provide information that will enable development of strategies to improve the efficiency of the Somali chilled meat export value chain as a way of increasing incomes to market actors. Primary data used was obtained from a rapid appraisal of chilled meat export marketing value chains in Somalia and a formal survey of market actors (brokers, small-scale traders, agents of exporters, exporters and airfreight operators). Secondary data obtained from a review of relevant literature and interviews with expert informants was also generated. The study identified a widely-recognized and consistently-applied grading system for slaughter stock. Quality requirements in importing countries were revealed to be well known throughout the chain, in that actors’ rankings of attributes were consistent within and between actor stages. Conversely, knowledge of health and safety requirements in the importing countries was known only to exporters. Other inconsistencies throughout the chain included the nature and strength of trading relationships: long-lived at exporter and agent level but short term and cash-based at producer level. Although exporters made payments mostly on the basis of carcass weight, agents of exporters paid based on per head of live animals. There is evidence of economies of scale, and of financial advantage in species specialization (specifically, goats) by traders. Most actors’ aspirations feature expansion, but they report investment funding as their main constraint. The report presents preliminary recommendations for public and private sectors, many predicated on further study. These focus on value addition and information sharing on what constitutes value, building of product identity and legally protecting its unique status, and coordination to address costs

    Beyond Race and Gender: Measuring Behavioral and Social Indicators of Pain Treatment Satisfaction in Older Black and White Cancer Patients

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    There are a number of factors that influence compliance with prescribed plans of care. However, there remains a need to identify the collective source health, behavioral, and social constructs have on treatment satisfaction. This study aimed to identify indicators of pain treatment satisfaction among older adults receiving outpatient treatment from a comprehensive cancer center in the southeast region of the United States. Data included a sample of 149 Black and White patients diagnosed with cancer, with the majority being White (85%) and female (57%). Patients were surveyed on questions assessing pain treatment satisfaction, pain severity, and additional social characteristics. A series of multivariate models were specified, whereby patients reporting multiple chronic conditions, poor communication, and perceived discrimination were less satisfied with treatment. Positive communication, higher self-efficacy, and fewer perceived discriminatory acts were significant among the female patients only. These findings suggest the need to develop clinical models that assess how these factors influence the degree of treatment satisfaction, while providing a comprehensive mechanism by which to service the long-term needs of older adults
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