Catherine M. Roe
Ganesh M. Babulal
Sarah Holtz Stout
David B. Carr
Monique M. Williams
Tammie L.S. Benzinger
Anne M. Fagan
Dave M. Holtzman
Beau M. Ances
John C. Morris
Wepresent a novel approach for analytically reducing a family of time-dependent multi-state quantum control problems to two-state systems. The presented method translates between SU(2) x SU(2) related n(2)-state systems and two-state systems, such that the former undergo complete population inversion (CPI) if and only if the latter reach specific states. For even n, the method translates any two-state CPI scheme to a family of CPI schemes in n(2)-state systems. In particular, facilitating CPI in a four-state system via real time-dependent nearest-neighbors couplings is reduced to facilitating CPI in a two-level system. Furthermore, we show that the method can be used for operator control, and provide conditions for producing several universal gates for quantum computation as an example. In addition, we indicate a basis for utilizing the method in optimal control problems.
This brief report derives the N in the penalty term of the Schwarz's (1978) Bayesian information criterion (BIC) for two-parameter logistic item response models. The results in this study show that the N is the number of persons for fixed item models, whereas it is the number of observations (the Number of Persons times the Number of Items) for random item models. Given these results, the authors recommend researchers to calculate the BIC or to validate the BIC value that shows in the output of software instead of accepting the output value without a further check of implicit assumptions made for the software.
Abstract: This paper focused on John Dewey's representations about mathematics education. Specifically, the objective was to explore Dewey's representations about the teaching of arithmetic and the number concept, based on texts he wrote after publishing the handbook The psychology of number (TPN) as a coauthor. Some of the sources were two letters written by Dewey, answering critics made of the TPN, and a review. The analysis was based on such concepts as representation, field, and social/institutional place, according to theorists as Roger Chartier, Michel de Certeau and Pierre Bourdieu. It is evident that the disputes between the fields, mainly of psychology and mathematics, concern the determination of who owns legitimacy to deliberate about the teaching of arithmetic. It is also possible to notice Dewey's representations about mathematics education, as he reiterates some aspects present in the TPN such as the psychical nature of number and the relation with the ideas of measurement and ratio.=09
Woodruff, L. K.
Kissel, D. E.
Cabrera, M. L.
Habteselassie, M. Y.
Hitchcock, R.
Gaskin, J.
Vigil, M.
Sonon, L.
Saha, U.
Romano, N.
Rema, J.
Cover crops can provide substantial quantities of N for subsequent crops, but estimating the amount of N that will be mineralized from residues is challenging. Complex interactions of residue chemistry with soil temperature and soil water content affect N mineralization during residue decomposition. A simulation model can describe these interactions and provide estimates of N mineralized if specific soil water and temperature data are available. Our objectives are (i) to describe a web-based N mineralization model and its operation, (ii) to calibrate the model with results from published N mineralization studies, and (iii) to validate it using field studies investigating decomposition of surface-applied or incorporated crimson clover (Trifolium incarnatum L.) or rye (Secale cereale L.) residues over 3 yr. Inputs required by the model include residue N, nonstructural carbohydrates, cellulose + hemi-cellulose, and lignin contents, as well as 5-yr average values of daily soil temperature and soil water content from a user-selected weather station. The model was successfully calibrated with published data from eight laboratory and field studies and was validated with data from field studies that used soil cores with cover crop residues. Simulated values of N mineralized were acceptable for incorporated residues but tended to overpredict N mineralized from surface residues because soil temperature and water content are not good drivers to simulate N mineralization from residues on the soil surface. Additional research is needed to develop algorithms to estimate temperature and water content/water potential of surface residues so they can be used as driver variables for the model.
Khalsa, Sat Darshan S.
Almanza, Carolina A.
Brown, Patrick H.
Smart, David R.
Our understanding of leaf litter carbon (C) and nitrogen (N) cycling and its effects on N management of deciduous permanent crops is limited. In a 30-day laboratory incubation, we compared soil respiration and changes in mineral N [ammonium (NH4+-N) + nitrate (NO3--N)], microbial biomass nitrogen (MBN), total organic carbon (TOC) and total non-extractable organic nitrogen (TON) between a control soil at N-15 natural abundance (N-15=3D1.08 parts per thousand) without leaf litter and a treatment with the same soil, but with almond (Prunus dulcis (Mill.) D.A. Webb) leaf litter that was also enriched in N-15 (N-15=3D213 parts per thousand). Furthermore, a two-end member isotope mixing model was used to identify the source of N in mineral N, MBN and TON pools as either soil or leaf litter. Over 30d, control and treatment TOC pools decreased while the TON pool increased for the treatment and decreased for the control. Greater soil respiration and significantly lower (p<0.05) mineral N from 3 to 15d and significantly greater MBN from 10 to 30d were observed for the treatment compared to the control. After 30d, soil-sourced mineral N was significantly greater for the treatment compared to the control. Combined mineral N and MBN pools derived from leaf litter followed a positive linear trend (R-2=3D0.75) at a rate of 1.39 g N g(-1) soil day(-1). These results suggest early-stage decomposition of leaf litter leads to N immobilization followed by greater N mineralization during later stages of decomposition. Direct observations of leaf litter C and N cycling assists with quantifying soil N retention and availability in orchard N budgets.
Biswas, Indranil; Kannan, S. Senthamarai; Nagaraj, D. S.
Let T be a maximal torus of PSL(n, C). For n >=3D 4, we construct a smooth compactification of PSL(n, C)/T as a geometric invariant theoretic quotient of the wonderful compactification <(PSL(n, C))over bar>for a suitable choice of T-linearized ample line bundle on <(PSL(n, C))over bar>. We also prove that the connected component, containing the identity element, of the automorphism group of this compactification of PSL(n, C)/T is PSL(n, C) itself.
New expressions for the Nuttall function are given in terms of the confluent Appell function . The derived closed-form expressions are valid for integer values of m and n satisfying with being an odd integer; this happens to be the case of many practical applications involving the Nuttall Q-function.
Recently an volume algorithm has been presented for convex bodies by Lovasz and Vempala, where is the number of dimensions of the convex body. Essentially the algorithm consists of several, interlocked simulational steps of slightly different natures. A computer implementation was later developed to gather some information about the numerical aspects of the algorithm, the number of dimensions in the examples was at most 10, and the errors of the results were somewhat dissatisfying. Now we present a parallel version of the improved algorithm, where variance reducing was added to make the algorithm faster, and the use of a GPU with 480 processors made experimentation easier. Computational results for convex bodies in dimensions ranging from 2 to 20 are presented as well.