3,542 research outputs found
Eddy current proximity gage for the determination of thickness of Portland cement concrete pavements
Multiple tests with eddy current proximity gage for determining thickness of concrete pavement
An Extension of the Reinforcement Contiguity Issue â The Effect of Retention in the Goal Box After Reinforcement
This study investigated one prediction of Guthrie\u27s theory of learning (1936, 1952)--that retention in the goal box after reinforcement increases the likelihood of incompatible responses to the goal stimuli and, thus, decreases learning. Three measures of learning were used: number of trials to criterion, total number of correct trials in the first twenty trials, and number of subjects who met criterion of five successive correct responses within forty trials
Revisiting the Application of the Exclusionary Rule to the Good Faith Exceptions in Light of Hudson v.Michigan
This Article examines other instances where the Supreme Court has historically held evidence inadmissible to determine whether such evidence should now be admissible in light of the Hudson v. Michigan analysis
Minimizing Communication in Linear Algebra
In 1981 Hong and Kung proved a lower bound on the amount of communication
needed to perform dense, matrix-multiplication using the conventional
algorithm, where the input matrices were too large to fit in the small, fast
memory. In 2004 Irony, Toledo and Tiskin gave a new proof of this result and
extended it to the parallel case. In both cases the lower bound may be
expressed as (#arithmetic operations / ), where M is the size
of the fast memory (or local memory in the parallel case). Here we generalize
these results to a much wider variety of algorithms, including LU
factorization, Cholesky factorization, factorization, QR factorization,
algorithms for eigenvalues and singular values, i.e., essentially all direct
methods of linear algebra. The proof works for dense or sparse matrices, and
for sequential or parallel algorithms. In addition to lower bounds on the
amount of data moved (bandwidth) we get lower bounds on the number of messages
required to move it (latency). We illustrate how to extend our lower bound
technique to compositions of linear algebra operations (like computing powers
of a matrix), to decide whether it is enough to call a sequence of simpler
optimal algorithms (like matrix multiplication) to minimize communication, or
if we can do better. We give examples of both. We also show how to extend our
lower bounds to certain graph theoretic problems.
We point out recently designed algorithms for dense LU, Cholesky, QR,
eigenvalue and the SVD problems that attain these lower bounds; implementations
of LU and QR show large speedups over conventional linear algebra algorithms in
standard libraries like LAPACK and ScaLAPACK. Many open problems remain.Comment: 27 pages, 2 table
Winter Wheat Response to Weed Control and Residual Herbicides
Italian ryegrass has become one of the most common and troublesome weeds of wheat production in the Southern United States. There are multiple reports in this region of Italian ryegrass herbicide resistance to acetyl-CoA carboxylase (ACCase), acetolactate synthase (ALS), and glyphosate herbicides. One commonality for Italian ryegrass resistance in this area is that most of these mechanisms of action for these herbicides are all postemergence (POST) applied. In order to have profitable soft red winter wheat production, applications of preemergence (PRE) herbicides with residual control of Italian ryegrass and other winter weed species would benefit growers. There are a very limited number of herbicides that can be applied at the time of wheat planting, primarily only when pyroxasulfone is registered for this timing. Research was conducted to establish weed control information when herbicides were applied to soft red winter wheat PRE, at wheat emergence (AE), or POST at Feekes stages 1.0â1.9, depending on herbicide label recommendations. Injury from any pyroxasulfone PRE treatments up to 120 g a.i. haâ1 was transient and did not affect wheat yield for any experiment. Italian ryegrass control was variable depending on location and year. Susceptible and diclofop-resistant Italian ryegrass control was 86% or greater with pyroxasulfone at 60 g a.i. haâ1 and greater with applied PRE. Italian ryegrass control was variable ranging from 27 to 49% with pendimethalin ME-applied PRE, diclofop at Feekes sage 1.0, and pinoxaden applied at Feekes stage 1.9
Stressful Life Events in Young Adults With Type 1 Diabetes in the U.S. T1D Exchange Clinic Registry
PurposeThe purpose was to test associations among stressful life events, frequency of missed insulin doses, and glycemic control in young adults with type 1 diabetes (T1D).DesignThe study was a crossâsectional descriptive secondary analysis.MethodsData from 2,921 participants (ages 18â26 years) in the U.S. T1D Exchange Clinic Registry were analyzed. Report of a stressful life event was defined as one or more positive responses on a 17âitem stressful life events index and defined as a dichotomous variable (yes or no). Frequency of missed insulin doses was measured using a single selfâreport item and collapsed into two levels (fewer than three times a week, three or more times a week). The glycosylated hemoglobin (A1c) level recorded at the time of enrollment was used to assess glycemic control.FindingsNearly half (48.6%) of the participants reported having a stressful life event during the previous year. The most frequently reported stressful life events were problems at work or school (16.1%), serious arguments with family members or a close friend (15.2%), and financial problems in the family (13.8%). Compared to the participants not reporting stressful life events, those who reported stressful life events were more likely to be older, female, with a higher educational attainment level, and not working or unemployed. Those who reported a stressful life event were more likely than those who did not to say they typically missed insulin doses at least three times a week and less likely to say they typically missed insulin doses fewer than three times a week (p < .001 adjusted for age, sex, race or ethnicity, educational attainment level, duration of T1D diagnosis, and insulin delivery method). Mean A1c level was higher for the group who reported having a stressful life event in the past 12 months compared to the group who did not (8.7 ± 1.8% vs. 8.2 ± 1.6%; adjusted p < .001). The results of a mediation analysis suggest that the measure of frequency of missed insulin doses may be a mediator of the relationship between recent stressful life events and glycemic control (Sobel test: ab = .841, 95% confidence interval = 0.064â1.618).ConclusionsThese findings suggest that, for young adults with T1D, the experience of stressful life events may increase their risk for poorer glycemic control, possibly by disrupting adherence with insulin doses.Clinical RelevanceFurther exploration of these relationships may allow for the potential for identifying those at risk and assisting them with more positive approaches to managing stressful events.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146646/1/jnu12428.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146646/2/jnu12428_am.pd
Analytical performance assessment of a novel active mooring system for load reduction in marine energy converters
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Reliability and storm survival of Marine Energy Converters are critical to their commercial development and deployment. The Intelligent Active Mooring System (IAMS) is a novel device intended to minimise extreme and fatigue loading in mooring lines through a non-linear loadâextension curve that is variable in operation to adjust to the prevailing metocean conditions. An analytical model of IAMS, validated by physical model tests at the Dynamic Marine Component test facility at the University of Exeter, is used in a numerical simulation of the performance of IAMS as part of the mooring system of the South West Mooring Test Facility buoy. A 10 m length of IAMS can reduce the rms line tension in normal operating conditions by up to 21% and the peak line tension in storm conditions by up to 21% when compared to braided nylon mooring lines. Peak line tension reductions of over 50% can be achieved if a longer IAMS unit is used. The resulting mooring system can be optimised to give load reductions in a wide range of metocean conditions; while variable pre-tension could be used for tidal range compensation or to ease access for installation and maintenance.The work reported here is part of a joint project between AWS Ocean Ltd., Teqniqa Systems Ltd. and the University of Exeter. The project was funded in part by the Technology Strategy Board (now Innovate UK) grant number 101970
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