3,727 research outputs found
Comparison of Two Year Classes of Hybrid Grass Carp and Grass Carp for Aquatic Plant Control
Two year classes of grass carp and F, hybrids resulting from bighead carp male x grass carp female were compared at various stocking densities for aquatic plant control. One and two year old grass carp exhibited higher survival rates and better growth rates than the same age hybrid grass carp. The presence of grass carp or hybrid grass carp decreased both Secchi disc transparencies and dissolved oxygen values. Grass carp had a greater negative effect upon these measurements because they removed the vegetation quicker than the hybrid grass carp. These apparent detrimental effects on water quality are necessary trade-offs for vegetation removal by any method. Grass carp and hybrid grass carp utilized Chara sp., Potamogeton pectinatus, Hydrodicton sp., Rhizoclonia sp., and Pithophora sp. Two year old hybrid grass carp required approximately twice as much time as the same age grass carp to eliminate dense growths of the vegetation listed above. One year old hybrid grass carp were slightly less effective than one year old grass carp at controlling these same plant species. However, it was extremely difficult for one or two year old hybrid grass carp to totally eliminate dense growths of these plant species except at high stocking densities. The use of mean vegetation heights to indirectly measure total plant biomass was unacceptable whenever unpreferred floating plant species were present. The hybrid grass carp appeared to be a poor alternative biological control for nuisance aquatic vegetation when compared directly to the grass carp
Drug diffusion from polymeric delivery devices: a problem with two moving boundaries
An existing model for solvent penetration and drug release from a spherically-shaped polymeric drug delivery device is revisited. The model has two moving boundaries, one that describes the interface between the glassy and rubbery states of polymer, and another that defines the interface between the polymer ball and the pool of solvent. The model is extended so that the nonlinear diffusion coefficient of drug explicitly depends on the concentration of solvent, and the resulting equations are solved numerically using a front-fixing transformation together with a finite difference spatial discretisation and the method of lines. We present evidence that our scheme is much more accurate than a previous scheme. Asymptotic results in the small-time limit are presented, which show how the use of a kinetic law as a boundary condition on the innermost moving boundary dictates qualitative behaviour, the scalings being very different to the similar moving boundary problem that arises from modelling the melting of an ice ball. The implication is that the model considered here exhibits what is referred to as ``non-Fickian'' or Case II diffusion which, together with the initially constant rate of drug release, has certain appeal from a pharmaceutical perspective
A parser for news downloads
This paper presents the Download Parser, a tool for handling text downloads from large online databases. Many universities have access to full-text databases which allow the user to search their holdings and then view and ideally download the full text of relevant articles, but there are important problems in practice in managing such downloads, because of factors such as duplication, unevenness of formatting standards, lack of documentation. The tool under discussion was devised to parse downloads, clean them up and standardise them, identify headlines and insert suitably marked-up headers for corpus analysis
Looking back or looking forward in corpus linguistics:what can the last 20 years suggest about the next?
Starting with a description of the software and hardware used for corpus linguistics in the late 1980s to early 1990s, this contribution discusses difficulties faced by the software designer when attempting to allow users to study text. Future human-machine interfaces may develop to be much more sophisticated, and certainly the aspects of text which can be studied will progress beyond plain text without images. Another area which will develop further is the study of patternings involving not just single words but word-relations across large stretches of text
Analysis of Network Clustering Algorithms and Cluster Quality Metrics at Scale
Notions of community quality underlie network clustering. While studies
surrounding network clustering are increasingly common, a precise understanding
of the realtionship between different cluster quality metrics is unknown. In
this paper, we examine the relationship between stand-alone cluster quality
metrics and information recovery metrics through a rigorous analysis of four
widely-used network clustering algorithms -- Louvain, Infomap, label
propagation, and smart local moving. We consider the stand-alone quality
metrics of modularity, conductance, and coverage, and we consider the
information recovery metrics of adjusted Rand score, normalized mutual
information, and a variant of normalized mutual information used in previous
work. Our study includes both synthetic graphs and empirical data sets of sizes
varying from 1,000 to 1,000,000 nodes.
We find significant differences among the results of the different cluster
quality metrics. For example, clustering algorithms can return a value of 0.4
out of 1 on modularity but score 0 out of 1 on information recovery. We find
conductance, though imperfect, to be the stand-alone quality metric that best
indicates performance on information recovery metrics. Our study shows that the
variant of normalized mutual information used in previous work cannot be
assumed to differ only slightly from traditional normalized mutual information.
Smart local moving is the best performing algorithm in our study, but
discrepancies between cluster evaluation metrics prevent us from declaring it
absolutely superior. Louvain performed better than Infomap in nearly all the
tests in our study, contradicting the results of previous work in which Infomap
was superior to Louvain. We find that although label propagation performs
poorly when clusters are less clearly defined, it scales efficiently and
accurately to large graphs with well-defined clusters
Assessment of shoulder active range of motion in prone versus supine:A reliability and concurrent validity study
Background: As swimming and surfing are prone dominant sports, it would be more sport specific to assess shoulder active range of motion in this position.
Objectives: To determine the reliability of the inclinometer and HALO© for assessing shoulder active range of motion in supine and prone and the concurrent validity of the HALO©. Concurrent validity is based on the comparison of the HALO© and inclinometer. To determine if active range of motion (AROM) differences exists between prone and supine when assessing shoulder internal (IR) and external rotation (ER).
Design: The design included clinical measurement, reliability and validity. Methods: Thirty shoulders (mean age = 26.8 years) without pathology were evaluated. Measurements were taken in supine and prone with both an inclinometer and HALO© device.
Results: Active ER ROM in prone was significantly higher than in supine when using both devices. Intra-rater reliability (within and between session) intraclass correlation coefficient (ICC) values ranged between 0.82–0.99 for both devices in supine and prone. An ICC test revealed a significant (p \u3c 0.01) correlation for both devices in IR and ER movements (ICC3,1 = 0.87 and ICC3,1 = 0.72), respectively.
Conclusion: This study has shown prone assessment of active ER and IR ROM to be a reliable and appropriate method for prone dominant athletes (swimmers and surfers). In this study greater ER ROM was achieved in prone compared to supine. This finding highlights the importance of standardizing the test position for initial and follow up assessments. Furthermore the HALO© and inclinometer have been shown to be reliable tools that show good concurrent validity
The Demise of American Musical Theatre of San Jose
In 2008, American Musical Theatre (AMT) of San Jose filed for bankruptcy after more than 74 years in business. In this thesis, I identify the factors – both internal and external – that contributed to its demise. Interviews with former employees and board members were conducted, and newspaper articles, tax records, and internal documents were examined to explore factors such as management effectiveness, AMT’s relationship with its community, fundraising, the decline of the subscription model, unions, and venue problems. The conclusions of this case study have implications regarding the intersection that now exists between non-profit and for-profit performing arts in the United States, as well as significance concerning the future of the performing arts in the San Francisco Bay Area
Water Quality Reporting Limits, Method Detection Limits, and Censored Values: What Does It All Mean?
The Arkansas Water Resources Center (AWRC) maintains a fee-based water-quality lab that is certified by the Arkansas Department of Environmental Quality (ADEQ). The AWRC Water Quality Lab analyzes water samples for a variety of constituents, using standard methods for the analysis of water samples (APHA 2012). The lab generates a report on the analysis, which is provided to clientele, and reports the concentrations or values as measured. Often times the concentrations or values might be very small, even zero as reported by the lab – what does this mean? How should we use this information? This document is intended to help our clientele understand the analytical report, the values, and how one might interpret information near the lower analytical limits. Every client wants the analysis of their water sample(s) to be accurate and precise, but what do we really mean when we say those two words? These words are often used synonymously or thought of as being the same, but the two words mean two different things. Both are equally important when analyzing water samples for constituent concentrations
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