Interferometric detection of spin-polarized transport in the depletion layer of a metal-GaAs Schottky barrier

It is shown that the Kerr rotation of spin-polarized electrons is modulated by the distance of the electrons from the sample surface. Time-resolved Kerr rotation of optically-excited spin-polarized electrons in the depletion layer of n-doped GaAs displays fast oscillations that originate from an interference between the light reflected from the semiconductor surface and from the front of the electron distribution moving into the semiconductor. Using this effect, the dynamics of the photogenerated charge carriers in the depletion layer of the biased Schottky barrier is measured.Comment: 10 pages, 4 figure

Some Biorthogonal Families of Polynomials Arising in Noncommutative Quantum Mechanics

In this paper we study families of complex Hermite polynomials and construct deformed versions of them, using a $GL(2,\mathbb{C})$ transformation. This construction leads to the emergence of biorthogonal families of deformed complex Hermite polynomials, which we then study in the context of a two-dimensional model of noncommutative quantum mechanics.Comment: 17 page

Transient response of photoexcited electrons: negative and oscillating current

Time-dependent current of the electrons excited in the conduction band after ultrafast interband photogeneration is studied theoretically. The transient photocurrent is calculated for the nonlinear regime of response to a stationary electric field. The response demonstrates transient absolute negative conductivity when the electrons are excited slightly below the optical phonon energy, while the periodic oscillations of the electric current appear after formation of the streaming distribution. The quenching of these peculiarities by the elastic scattering of electrons is also considered.Comment: 5 pages, 3 figure

Fluorides, orthodontics and demineralization: a systematic review

Objectives: To evaluate the effectiveness of fluoride in preventing white spot lesion (WSL) demineralization during orthodontic treatment and compare all modes of fluoride delivery. Data sources: The search strategy for the review was carried out according to the standard Cochrane systematic review methodology. The following databases were searched for RCTs or CCTs: Cochrane Clinical Trials Register, Cochrane Oral Health Group Specialized Trials Register, MEDLINE and EMBASE. Inclusion and exclusion criteria were applied when considering studies to be included. Authors of trials were contacted for further data. Data selection: The primary outcome of the review was the presence or absence of WSL by patient at the end of treatment. Secondary outcomes included any quantitative assessment of enamel mineral loss or lesion depth. Data extraction: Six reviewers independently, in duplicate, extracted data, including an assessment of the methodological quality of each trial. Data synthesis: Fifteen trials provided data for this review, although none fulfilled all the methodological quality assessment criteria. One study found that a daily NaF mouthrinse reduced the severity of demineralization surrounding an orthodontic appliance (lesion depth difference –70.0 µm; 95% CI –118.2 to –21.8 µm). One study found that use of a glass ionomer cement (GIC) for bracket bonding reduced the prevalence of WSL (Peto OR 0.35; 95% CI 0.15–0.84) compared with a composite resin. None of the studies fulfilled all of the methodological quality assessment criteria. Conclusions: There is some evidence that the use of a daily NaF mouthrinse or a GIC for bonding brackets might reduce the occurrence and severity of WSL during orthodontic treatment. More high quality, clinical research is required into the different modes of delivering fluoride to the orthodontic patient

Development of A New Algorithm For Optimal Solution Of Transportation Problems

This paper leads to an Algorithm/technique to solve optimal solution occurring in Transportation problems. In Transportation Problems by presenting a new algorithm to choose the Absolute differences of boundary cost cells. This New Algorithm lesser time than the existing Transportation method to get the optimal solution using initial basic feasible solution. Proposed technique/algorithm is better choice to get optimal solution without finding initial basic feasible solution and hence the proposed algorithm is useful to get optimal solution Transportation problems. Key words:- Transportation Problems, Absolute differences of boundary cost cells, Modified Distribution (M.O.D.I) Method, Initial Basic feasible solution, Optimum solution. DOI: 10.7176/MTM/9-1-0

An Improved Algorithm to Solve Transportation Problems for Optimal Solution

In this paper, we have developed an algorithm to obtain initial basic feasible solution of transportation problems where the object is to minimize the transportation cost. The proposed method is compared with well-known existing methods including Least-Cost Method and North-West Corner Method and is found to yield better results. Feasible solution from the proposed method leads to solution closest to the optimal solution; and in some numerical examples same as the optimal solution. Key words: Transportation problem, Initial Basic Feasible Solution, Optimal Solutio

OCL Plus: Processes and Events in Object-Centred Planning

An important area in AI Planning is the expressiveness of planning domain specification languages such as PDDL, and their aptitude for modelling real applications. This paper presents OCLplus, an extension of a hierarchical object centred planning domain definition language, intended to support the representation of domains with continuous change. The main extension in OCLplus provides the capability of interconnection between the planners and the changes that are caused by other objects of the world. To this extent, the concept of event and process are introduced in the Hierarchical Task Network (HTN), object centred planning framework in which a process is responsible for either continuous or discrete changes, and an event is triggered if its precondition is met. We evaluate the use of OCLplus and compare it with a similar language, PDDL+