144 research outputs found
Alien Registration- Hemeon, Ernest (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/23239/thumbnail.jp
Polyculture bioremediation: An analysis of potential nitrogen assimilation and removal by Mya Arenaria, Gracilaria Tikvahiae and Ulva Lactuca harvests in the Corsica River, MD
An analysis of nitrogen bioremediation in a tidal tributary of the Chesapeake Bay by the use of a hypothetical bivalve and macroalgae polyculture covering 1%, 3% and 5% of the Corsica River bottom area. This study was performed to illustrate the role ecosystem services play in managing diffuse watershed pollution, particularly nitrogen, resulting in water quality and living resource degradation. Excess concentrations of nitrogen in the Corsica River estuary lead to seasonal eutrophication and subsequent hypoxic events. Mya arenaria L. and Gracilaria tikvahiae (McLachlan, 1979) were chosen for this theoretical study due to their high assimilative capacities for nitrogen and established commercial value, whereas Ulva lactuca L. was analyzed as a biofouling harvest to increase the harvest nitrogen sink. M. arenaria nitrogen assimilation was calculated from literature values of nitrogen content in tissue, whereas G. tikvahiae was simulated from an existing macroalgae submodel. M. arenaria nitrogen removal ranged from 1000 kg N to 7000 kg of nitrogen per year and did not reflect M. arenaria mortality or nitrogen remineralization from biodeposits. Simulation of the model indicates that G. tikvahiae can remove between 51-255 kg of nitrogen per year and U. lactuca only removes 35-103 kg of nitrogen per year. Results indicate that the polyculture of M. arenaria and G. tikvahiae in the Corsica River can adequately reduce net nitrogen levels and demonstrate the use of bioremediation as a possible nutrient management tool for estuary restoration
OCEAN QUAHOG (ARCTICA ISLANDICA) POPULATION DYNAMICS: SEX-BASED DEMOGRAPHICS AND REGIONAL COMPARISONS IN THE NORTHWEST ATLANTIC
Arctica islandica (ocean quahog) is the longest-lived bivalve on Earth. Individuals on the deep continental shelf of the Mid-Atlantic (US) can survive for centuries, and when found in the colder, boreal waters of Iceland, ages over 500 years can be reached. The ocean quahog is important in the US, yet very little is known about the resiliency of the ocean quahog stock to fishing activity, and ocean quahog recruitment patterns over time. To quantify and constrain age-reader error prior to age analysis, a triple-method error protocol was developed for A. islandica that included age-reader bias, precision, and error frequency. The error protocol was implemented for samples collected in 2017 from Georges Bank (GB) and Long Island (LI) in the US Mid-Atlantic. Assumptions of prolonged lapses in recruitment were not substantiated for either the GB or LI populations, yearly cohorts were observed for the past century, and both populations presented recruitment pulses in regular 8-y periods. The oldest animal at GB was a 261-year-old male, and the oldest animal at LI was a 310-year-old male. Estimated ages from this study are older than previously reported for the US Mid-Atlantic. Total mortality was higher at GB than LI, and higher for GB females than GB males. Constructed ALKs were reliable but not interchangeable between sexes or populations. The population sex ratio at GB was 1.1.1 (F:M), whereas LI was 1:1.4 and relatively deficient in fishery-sized females. The Modified Tanaka growth model was the best fit growth function for A. islandica age-length data from the Mid-Atlantic, and growth models changed over time dependent on birth year. Indexed growth from both populations expressed significant 31-y frequency periods, where GB growth lagged behind LI between 1760-1950. Growth rates of A. islandica from both populations have continuously increased since the mid-1800s, female growth rates are faster than males, and growth rates at GB are generally faster than those at LI. Females dominated large size classes, males dominated small size classes, and evidence strongly suggests that this species is sexually dimorphic
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The magnetic and turbulent evolution of the Taurus Molecular Cloud.
Grammatical Aspect, Temporal Adverbs, and Situation Models
Grammatical aspect and temporal cues have been shown to impact discourse processing. To explore this further, we contrasted temporal adverbs that move narrative timelines forward or backward. Although previous research has examined timelines independently, it was yet to be explored how timeline adverbs impact discourse processing when grammatical aspect and temporal cues are also manipulated. The experiment involved a sentence-completion task which allowed us to measure availability of target discourse concepts in situation models. Results showed main effects for grammatical aspect, temporal shifts, and narrative timeline directions. Three two-way interactions were found. The results demonstrated support for the iconicity assumption and determined that grammatical aspect, time shifts, and narrative timeline direction in texts impact discourse processing
Recyclable palladium(0)-catalyzed addition of silylstannanes to terminal alkynes in ionic liquids
x, 109 leaves : ill. ; 28 cm.Includes abstract.Includes bibliographical references (leaves 104-109).Ionic liquids have been used as solvents for many different organic reactions, often providing rate enhancements, selectivity improvements, and affording better yields compared to conventional solvents. In this study, the palladium(0)-catalyzed addition of trimethyl(tributylstannyl)silane and diphenylmethyl(tributylstannyl)silane to terminal alkynes is investigated using two different ionic liquids, 1- n -butyl-3-methylimidazolium hexafluorophosphate and 1- n -butyl-3-methylimidazolium tetrafluoroborate, under biphasic conditions using diethyl ether as a co-solvent. Five terminal alkynes were used, phenylacetylene, 1-decyne, 5-hexyn-1-ol, 5-hexyn-1-ol THP ether, and 6-chlorohexyne. In general, reactions between the silylstannanes and alkynes proceeded efficiently in both ionic liquids to give quantitative or near quantitative yields of their addition products as a single isomer.
Ionic liquids have gained much popularity of late due to their ability to immobilize transition metal catalysts, allowing them to be recycled due to the nonvolatile nature of ionic liquids. The tetrakis(triphenylphosphine)palladium(0) catalyst used in these silylstannation reactions was immobilized in both ionic liquids and shown to be extensively recyclable without loss of activity. Ionic liquid/catalyst systems were recycled ten times in the reaction of phenylacetylene with trimethyl(tributylstannyl)silane
A Growth Model for \u3ci\u3eArctica islandica\u3c/i\u3e: The Performance of Tanaka and the Temptation of Von Bertalanffy—Can the Two Coexist?
Organisms increase in size over time (age) due to excess assimilation over metabolic (respiration) energy demands. Most organisms reach a maximum size with increasing age as gain and loss balance. The von Bertalanffy length-at-age relationship, which is commonly used in fishery assessment calculations, imposes such a maximum size. However, some fished species, such as ocean quahogs, Arctica islandica, are long lived and continue to grow at old age. The Tanaka age-at-length relationship has continued growth at old age, but is rarely used in stock assessment models. A modified form of the von Bertalanffy model is presented, which mimics the continued growth at old age of the Tanaka model by allowing the growth parameter (K) to decline with age. This form is suitable for inclusion in stock assessment models based on von Bertalanffy. The proposed model matches Tanaka curves with precision appropriate for the scatter of data used to fit the curves. The observations of ocean quahog length at age and growth rate from New Jersey and Georges Bank demonstrate the ability of the modified von Bertalanffy relationship to represent continued growth at old age for this fished species. Simulated data generated with continued growth at old age were fit with the Stock Synthesis model (SS3). Results comparing traditional and modified growth relationships showed that the original von Bertalanffy model can reasonably approximate modest nonasymptotic growth as long as the number of observations is sufficient to constrain the parameter values
Attainability of Accurate Age Frequencies for Ocean Quahogs (Arctica islandica) Using Large Datasets: Protocol, Reader Precision, and Error Assessment
Ocean quahogs (Arctica islandica) are the longest lived bivalve on Earth. Individuals on the deep continental shelf off Georges Bank can survive for centuries, and in the colder, boreal waters of Iceland, ages over 500 y can be reached. Ocean quahog landings in the United States represent a $24 million industry, yet assessment models operate with no age data because of the substantial sample size required to develop adequate population age distributions for such a long-lived species, the unknown error associated with age estimates, and the extensive time and financial investment required to create production-scale age datasets. Inclusion of age data for this species requires precision metrics to evaluate aging uncertainty such as percent agreement, percent error, coefficient of variation, and tests of bias. To move forward using error-validated age-composition data, a 3-fold error protocol was developed using a large dual-reader dataset (n = 610) from Georges Bank. First, a proxy age-validation study was performed to corroborate an aging method, followed by error evaluation in the context of age-reader bias, precision, and error frequency. Error thresholds were established for each of the three error methods. Georges Bank samples ranged from 33 to 261 y of age and met the predetermined error thresholds for bias (conditionally because of significant and nonsignificant results), precision (average coefficient of variation less than 7%), and error frequency (less than 10%). Consequently, age estimates were deemed acceptable to support age frequency analyses. Precision and bias error were greatest for the youngest animals and, in the context of age-reader bias, error rates were higher for young male ocean quahogs than for young females. Improved age validation of young, sex-differentiated A. islandica will constrain aging error and guide refinement of both aging and age-error protocols
The question of homogeneity inside a chimney: application of ISO 13528 to stack emission proficiency tests
Thermal reversion of spirooxazine in ionic liquids containing the [NTf2]- anion
We have compared the rate of thermal reversion of Spirooxazine (SO) from its merocyanine (MC) form within ionic liquids and molecular solvents. Et(30) and Kamlet-Taft parameter studies indicate ILs are comparable to polar protic and aprotic solvents. The observed reversion kinetics within the ionic liquids were slower than that of molecular solvents with similar polarity, indicating a greater degree of interactions between the ionic liquid ions and the zwitterionic MC isomer, which led to increased lifetimes for the MC-ion complexes. Pre-metathesis cleaning of precursor salts was found to be necessary in order to obtain spectroscopic grade ILs for physiochemical analysis using solvatochromic probe dyes
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