A Eutrophication Model of the White River Basin Above Beaver Reservoir in Northwest Arkansas

With national interest focused on man’s ever increasing degradation of the waters in this nation, it is clearly evident that an accurate assessment of all parameters influencing water quality needs to be made. Moreover, nutrient levels and budgets reflecting eutrophication trends are important parameters in the overall factors effecting water quality in lakes and reservoirs. The ability to predict future eutrophication levels will greatly enhance the retardation of the eutrophication process. Through mathematical simulation of this process, eutrophication can be analyzed and intelligent decisions regarding water quality management can be made

Do High School Exit Exams Influence Educational Attainment or Labor Market Performance?

State requirements that high school graduates pass exit exams were the leading edge of the movement towards standards-based reform and continue to be adopted and refined by states today. In this study, we present new empirical evidence on how exit exams influenced educational attainment and labor market experiences using data from the 2000 Census and the National Center for Education Statistics' Common Core of Data (CCD). Our results suggest that the effects of these reforms have been heterogeneous. For example, our analysis of the Census data suggests that exit exams significantly reduced the probability of completing high school, particularly for black students. Similarly, our analysis of grade-level dropout data from the CCD indicates that Minnesota's recent exit exam increased the dropout rate in urban and high-poverty school districts as well as in those with a relatively large concentration of minority students. This increased risk of dropping out was concentrated among 12th grade students. However, we also found that Minnesota's exit exam lowered the dropout rate in low-poverty and suburban school districts, particularly among students in the 10th and 11th grades. These results suggest that exit exams have the capacity to improve student and school performance but also appear to have exacerbated the inequality in educational attainment.

Traceability-based change management in operational mappings

This paper describes an approach for the analysis of changes in model transformations in the Model Driven Architecture (MDA). Models should be amenable to changes in user requirements and technological platforms. Impact analysis of changes can be based on traceability of model elements. We propose a model for generating trace links between model elements and study scenarios for changes in source models and how to identify the impacted elements in the target model

Inter-rater reliability of treatment fidelity and therapeutic alliance measures for psychological therapies for anxiety in young people with autism spectrum disorders

Objectives: This article presents work undertaken to establish inter-rater reliability for a measure of treatment fidelity and a measure of therapeutic alliance for therapies for anxiety for young people with autism spectrum disorders. The discussion and decision-making processes behind achieving consensus of raters are rarely published. Margolin et al. (1998) have highlighted this issue and called for researchers to communicate the details of their observational and rating procedures. This article is a response to their call for greater transparency so that these methods are readily accessible for comparison with other studies. Methods: Participants were young people with autism spectrum disorders receiving treatment for anxiety, clinical staff treating these young people and the independent raters assessing the treatment sessions. We report: (i) the processes involved in establishing inter-rater reliability for two instruments, (ii) the results obtained with a sample of young people with autism spectrum disorders using these instruments. Results and conclusions: Results demonstrate that it was possible to attain satisfactory inter-rater reliability with each of these two instruments with a client group with autism spectrum disorders, even though the instruments were originally designed for typically-developing populations

Decay Process for Three - Species Reaction - Diffusion System

We propose the deterministic rate equation of three-species in the reaction - diffusion system. For this case, our purpose is to carry out the decay process in our three-species reaction-diffusion model of the form $A+B+C\to D$. The particle density and the global reaction rate are also shown analytically and numerically on a two-dimensional square lattice with the periodic boundary conditions. Especially, the crossover of the global reaction rate is discussed in both early-time and long-time regimes.Comment: 6 pages, 3 figures, Late

Multiple Front Propagation Into Unstable States

The dynamics of transient patterns formed by front propagation in extended nonequilibrium systems is considered. Under certain circumstances, the state left behind a front propagating into an unstable homogeneous state can be an unstable periodic pattern. It is found by a numerical solution of a model of the Fr\'eedericksz transition in nematic liquid crystals that the mechanism of decay of such periodic unstable states is the propagation of a second front which replaces the unstable pattern by a another unstable periodic state with larger wavelength. The speed of this second front and the periodicity of the new state are analytically calculated with a generalization of the marginal stability formalism suited to the study of front propagation into periodic unstable states. PACS: 47.20.Ky, 03.40.Kf, 47.54.+rComment: 12 page

Evaporation Rate Study and NDMA Formation from UDMH/NO2 Reaction Products

Laboratory samples of uns-dimethylhydrazine (UDMH) fuel/oxidizer (nitrogen dioxide) non-combustion reaction products (UFORP) were prepared using a unique permeation tube technology. Also, a synthetic UFORP was prepared from UDMH, N-nitrosodimethylamine (NDMA), dimethylammonium nitrate, sodium nitrite and purified water. The evaporation rate of UFORP and synthetic UFORP was determined under space vacuum (approx 10(exp -3) Torr) at -40 ?C and 0 ?C. The material remaining was analyzed and showed that the UFORP weight and NDMA concentration decreased over time; however, NDMA had not completely evaporated. Over 85% of the weight was removed by subjecting the UFORP to 10(-3) Torr for 7 hours at -40 ?C and 4 hours at 0 ?C. A mixture of dimethylammonium nitrate and sodium nitrite formed NDMA at a rapid rate in a moist air environment. A sample of UFORP residue was analyzed for formation of NDMA under various conditions. It was found that NDMA was not formed unless nitrite was added

Diels-Alder Trapping of Photochemically Generated o-Quinodimethane Intermediates: An Alternative Route to Photocured Polymer Film Development

Photolysis of o-methylphenyl ketones generates bis-o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions. This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis-(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate ester monomers for the development of acrylic ester copolymer blends. Irradiation of cyclohexanone solutions of the bis-(o-methylphenyl ketone)s and acrylate esters produce thin polymer films. Solid state 13C NMR data indicated 47- 100% reaction of the bis-(o-methylphenyl ketone)s, depending on experimental conditions, to yield the desired products. DSC and TGA analyses were performed to determine the glass transition temperature, T,, and onset of decomposition, Td, of the resulting polymer films. A statistical Design of Experiments approach was used to obtain a systematic understanding of the effects of experimental variables on the extent of polymerization and the final polymer properties