Flow pattern dynamics in convecting liquid helium.

We present experimental data which correlate thermal measurements and flow visualization in convecting liquid 4He. For a small range R(C)R1, generating thermal oscillations as in earlier reports. At higher R values the time dependence becomes aperiodic with the surprising appearance of spiral-defect chaos at an aspect ratio smaller than has previously been reported.

Streamwater nitrate concentrations in six agricultural catchments in Scotland.

The concentrations of nitrate-N (NO3-N) in catchment inputs and outputs have been compared and contrasted between 6 farm catchments in Scotland, 3 in the West and 3 in the North-East. Forms of intensive animal farming ranging between beef and dairy cattle, sheep and poultry give different sources for potential NO3-N leakage from the systems. While stream reaches bordered by intensive cereal production give rise to the largest inputs to surface waters, climatic influences result in the more-efficient use of fertilizer- and farm waste-N in the West, and an enhanced potential for N-loss to waters in the cooler North-East, regardless of the N-inputs being considerably lower in the latter region. Although the EC Nitrate Directive limit of 11.3 mg NO3-N 1(-1) was not exceeded, peak values occurring during summer baseflows and autumn soil rewetting were commonly larger than the 'target' maximum concentration of 5.65 mg NO3-N 1-1.

Adjustment of young adults with mental retardation in community settings: comparison of parametric and nonparametric statistical techniques.

The impact of four different statistical techniques on the interpretive process using data obtained from young adults with mental retardation in applied settings was evaluated. Our hypothesis was that no difference exists across levels of mental retardation for four dependent variables, jointly or separately, using (a) parametric multivariate analysis of variance, (b) nonparametric multivariate analysis of variance, (c) multiple nonparametric analyses of variance, and (d) multinomial logistic regression. The pattern of significance remained the same across the three classical and quasi-classical designs. Substantive differences were found using the fourth technique, multinomial logistic regression. The four techniques were compared using interpretational as well as statistical criteria.

Empirical analysis of multidimensional measures of community adjustment for young adults with mental retardation.

Confirmatory factor analysis procedures were used to evaluate multidimensional measures of community adjustment in a sample of 239 young adults with mild to severe mental retardation. Alternative measurement models were evaluated in one-half of the sample, with the final model cross-validated in the second half of the sample. The final cross-validated model was also evaluated as a function of level of retardation. Evidence was found for at least six broad dimensions of community adjustment when combined with other multidimensional research findings. The measurement of one dimension varied as a function of degree of retardation. Use of validated multidimensional measures of community adjustment in future research studies was discussed.

High school graduation requirements for students with disabilities.

Although increasing the high school graduation rate is now a national goal, requirements for graduation are not set at the national level. And, although the goal is said to include students in special education programs, what high school graduation means for these students is not clear. We collected documentation from state departments of education to examine high school graduation requirements for students in general, and for students with disabilities. Forty-four states use Carnegie course unit requirements ranging from 10.35 to 24.00 credits. Seventeen states currently have requirements for either a minimum competency test or an exit exam. Local education agencies in several states have the option of establishing more stringent requirements than called for in state guidelines. Exit documents that are awarded to students with disabilities (e.g., standard diplomas, modified diplomas, certificates of attendance) also vary from state to state, with similar requirements sometimes earning different types of exit documents in different states. These inconsistencies in graduation requirements and their implications for students with learning disabilities are discussed.

The relationship between instructional and assessment accommodations in an inclusive state accountability system.

We investigated the kinds of instructional and assessment accommodations students with disabilities receive, and the extent to which instructional accommodations match assessment accommodations. Most students who had IEPs in specific content areas received instructional accommodations in those areas, and there were no differences by disability type. We provide data on the specific types of accommodations used. Overall, students' assessment accommodations matched their instructional accommodations, though many students received testing accommodations that had not been received in instruction. Implications are discussed for IEP teams who make decisions about instructional and assessment accommodations.

Community integration of young adults with mental retardation: a multivariate analysis of adjustment.

The purpose of the present study was to determine whether differences in community adjustment existed for three groups of young adults with mental retardation using data organized on the basis of four empirically validated factors identified in prior research. A descriptive discriminant function analysis was used as a follow-up to a statistically significant multivariate analysis of variance F-ratio. Results obtained from the discriminant analysis indicated that five variables (number of limiting factors, earned income, number of support services, living arrangement, number of daytime activities) contributed substantively to separation of the three group centroids.

Relationship between measures of adaptive functioning and community adjustment for adults with mental retardation.

This study investigated the concurrent relations between measures of adaptive/maladaptive behavior and community adjustment in a sample of 239 adults with mild to severe degrees of mental retardation. Using canonical correlation procedures and multidimensional community adjustment measures, the investigators found significant relations between the measures of behavior and several community adjustment dimensions. The results provided evidence for the criterion-related validity of measures of adaptive/maladaptive behavior and suggested that such skills provide an important contribution to community adaptation and to program planning and decision making for individuals with mental retardation.

Open enrollment and students with disabilities: issues, concerns, fears, and anticipated benefits.

Open enrollment is a hotly debated form of educational choice. More than 25 states have legislation establishing or expanding public school choice options. At an issues clarification working session, professionals, legislators, policymakers, parents, and students described issues and generated implications for serving students with disabilities. Participants identified three kinds of issues for districts and students: outcome, implementation, and demographic. Participants also expressed other concerns about choice: pupil benefit, parent involvement (or convenience), teacher/administrator job protection, change, and teacher workload.

The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals.

High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10(12). The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A(2)Π3/2 (v(') = 2) ← X(2)Π3/2 (v(″) = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.

Effects of structural variations in elaboration on learning by EMR and nonretarded children.

The effects of three elaboration structures (compound sentences, complex sentences, and paragraphs) on the paired-associate learning and reversal of 30 8- to 10-year-old nonretarded and 30 8- to 10-year-old EMR children were investigated. Analyses of trials-to-criterion, first trial errors, and reversal errors did not reveal any differences in the effects of the three elaboration structures. Results of the present study indicate that given constant meaning and relational factors, some forms of surface structure differneces (compound sentences vs. complex sentence vs. paragraph) are not significant in determining a child's ability to understand an elaboration or to use it in a learning situation. There was no population difference found in the analysis of first-trial errors, although small significant differences between the nonretarded and EMR children were found in the analyses of trials-to-criterion and reversal performance.

Instructional ecology and academic responding time for students at three levels of teacher-perceived behavioral competence.

Thirty third and fourth grade students, ages 8-10 years, were observed systematically over two entire school days to examine the nature of instruction and academic responding time for students at varying levels of teacher-perceived behavioral competence. Data were recorded on six categories in 10-sec intervals. While the amount of time spent in active academic responses (about 45 min in a typical school day) did not differ significantly between groups, it was found that students perceived to be lower in behavioral competence spent more time engaged in certain inappropriate behaviors and received more teacher disapproval. Yet, students grouped on the basis of teachers' perceptions of their behavioral competence did not differ on the majority of instructional or student responding variables. Findings related to the relationship between responding times and achievement also are presented. Implications of findings for understanding the classroom ecology for students exhibiting behavior problems are discussed.

A kinetic study of the reaction of horseradish peroxidase with hydrogen peroxide.

A kinetic study has been carried out over the pH range of 2.63-9.37 for the reaction of horseradish peroxidase with hydrogen peroxide to form compound I of th;e enzyme. Analysis of the results, indicates that there are two kinetic influencing, ionizable groups on the enzyme with pKa values of 3.2 and 3.9. Protonation of these groups results in a decrease in the rate of reaction of the enzyme with H2O2. A previous study of the kinetics of cyanide binding to horseradish peroxidase (Ellis, W.D. & Dunford, H.B.: Biochemistry 7, 2054-2062 (1968)) has been extended to down to pH 2.55, and analysis of these results also indicates the presence of two kinetically important ionizable groups on the enzyme with pKa values of 2.9 and 3.9.

Outerdirectedness in retarded children as a function of sex of experimenter and sex of subject.

Effects of same- and cross-sex experimenters on attentive behavior and learning of 64 EMR children were examined in two conditions: experimenter not present (not in) or experimenter present and providing cues relevant to task mastery (relevant cue). A significant Sex of Experimenter X Sex of Subject interaction was found in the learning data, with girls performing significantly better than boys when the experimenter was male, the reverse pattern was evident, although not statistically significant, when the experimenter was female. Some effects were also found for individual experimenters. Although significantly more nontask orienting responses were observed in the relevant-cue condition, subjects in this condition performed as well on the learning task as did subjects in the not-in condition. Reversal trials showed greater glancing and superior performance in the relevant-cue condition.

Efficiency considerations in delivering special education services to persons with severe mental retardation.

The basic question addressed in this paper is whether formal benefit-cost and effectiveness-cost analyses might allow us to determine whether the outcomes of particular special education services are being offered in their most efficient manner. In attempting to answer this question, we focused upon measuring as many of the cost and outcomes as possible (in both monetary and other terms) from two specialized schools serving youth with severe mental retardation. We examined a number of alternative assumptions for illustrating some of the problematic issues in the use of such evaluation techniques.

Food-plant effects on larval performance do not translate into differences in fitness between populations of Panolis flammea (Lepidoptera: Noctuidae).

In the UK, Panolis flammea (Denis & Schiffermüller) is a pest of monocultures of non-native lodgepole pine Pinus contorta Douglas, but not of the indigenous host Scots pine P. sylvestrisL. This difference in population dynamics may be due to the adaptation of P. flammea populations to the phenology, chemical composition and natural enemy complement of lodgepole pine. To ascertain if there was local adaptation of P. flammea populations to lodgepole pine, this study tested for improved performance of both larvae and adults on the host plant species from which they were sourced, compared with their performance on the alternative host plant species. No difference was found in the relative mean performance of populations sourced from Scots pine or lodgepole pine plantations, when fed on Scots or lodgepole pine foliage. Larvae grew faster on Scots pine but this difference did not translate into differences in pupal weight, female body weight or fecundity. Indeed, those insects that had fed on lodgepole pine had a longer lifespan than those that had fed on Scots pine, which, if translated into greater probability of mating or higher fecundity, could contribute to the observed outbreak dynamics in the field. The prediction that the observed outbreak dynamics of P. flammea can be explained by the existence of populations locally adapted to lodgepole pine was not supported. These results cast doubt on the use of larval growth parameters as surrogates of fitness in Lepidoptera.