Interactive Tutorials For Upper Level Quantum Mechanics Courses

This thesis explores the ongoing need for interactive tutorials in the upper level undergraduate Quantum Mechanics course. It first summarizes the development and evaluation of tutorials at the introductory physics level by others, and then challenges the belief that upper level students do not need this type of intervention by citing research in student difficulties in learning Quantum Mechanics. Physics Education research shows that there are common student misconceptions that persist even in the upper level undergraduate courses such as Quantum Mechanics. Cognitive research serves as a guide for effective curriculum design. A description of the iterative process for developing and evaluating the tutorials is discussed. The development and evaluation of "The Time Evolution of a Wave Function" Quantum Interactive Learning Tutorial (QuILT) is described in detail. Finally, the success of the QuILT in reducing the common misconceptions about time evolution is discussed

The upper normal limit of serum alanine aminotransferase in Golestan Province, Northeast Iran

Background: The objective of this study was to determine the upper normal limit of serum alanine aminotransferase level in a population-based study in Golestan Province, northeast Iran. Methods: From the randomly invited individuals (2,292), 698 out of the 916 males and 1,351 out of the 1,376 females participated in the study (participation rate: 76.2 and 98.1, respectively). One hundred and twenty-one participants were excluded due to positive hepatitis B surface antigen or hepatitis C virus antibody and/or drinking more than 20 grams of alcohol per day. A total of 1,928 participants (1300 females) were included. The upper normal limit of serum alanine aminotransferase level was defined as the 95th percentile. Results: The upper normal limit of serum alanine aminotransferase level in normal weight and nondiabetics was significantly lower than the total study group (36 versus 45 U/L). Serum alanine aminotransferase level was independently associated with male gender, body mass index, and diabetes mellitus (OR=2.05; 95Cl: 1.44 - 2.94, OR=2.76; 95Cl: 1.84 - 4.13, and OR=2.96; 95Cl: 1.56-5.61, respectively). Conclusion: Considering the lower calculated upper normal limit in normal weight nondiabetic participants in this study, we recommend setting new upper normal limit for serum alanine aminotransferase level, It seems reasonable to set upper normal limit for serum alanine aminotransferase level in males and females separately

Improved models of upper-level wind for several astronomical observatories

An understanding of wind speed and direction as a function of height are critical to the proper modeling of atmospheric turbulence. We have used radiosonde data from launch sites near significant astronomical observatories and created mean profiles of wind speed and direction and have also computed Richardson number profiles. Using data from the last 30 years, we extend the 1977 Greenwood wind profile to include parameters that show seasonal variations and differences in location. The added information from our models is useful for the design of adaptive optics systems and other imaging systems. Our analysis of the Richardson number suggests that persistent turbulent layers may be inferred when low values are present in our long term averaged data. Knowledge of the presence of these layers may help with planning for adaptive optics and laser communications.Comment: 21 pages, 15 Figures, 8 table

Multi-Level Steganography: Improving Hidden Communication in Networks

The paper presents Multi-Level Steganography (MLS), which defines a new concept for hidden communication in telecommunication networks. In MLS, at least two steganographic methods are utilised simultaneously, in such a way that one method (called the upper-level) serves as a carrier for the second one (called the lower-level). Such a relationship between two (or more) information hiding solutions has several potential benefits. The most important is that the lower-level method steganographic bandwidth can be utilised to make the steganogram unreadable even after the detection of the upper-level method: e.g., it can carry a cryptographic key that deciphers the steganogram carried by the upper-level one. It can also be used to provide the steganogram with integrity. Another important benefit is that the lower-layer method may be used as a signalling channel in which to exchange information that affects the way that the upper-level method functions, thus possibly making the steganographic communication harder to detect. The prototype of MLS for IP networks was also developed, and the experimental results are included in this paper.Comment: 18 pages, 13 figure

Charge Density Wave in Two-Dimensional Electron Liquid in Weak Magnetic Field

We study the ground state of a clean two-dimensional electron liquid in a weak magnetic field where $N \gg 1$ lower Landau levels are completely filled and the upper level is partially filled. It is shown that the electrons at the upper Landau level form domains with filling factor equal to one and zero. The domains alternate with a spatial period of order of the cyclotron radius, which is much larger than the interparticle distance at the upper Landau level. The one-particle density of states, which can be probed by tunneling experiments, is shown to have a pseudogap linearly dependent on the magnetic field in the limit of large $N$.Comment: Several errors correcte

The upper normal limit of serum alanine aminotransferase in Golestan Province, Northeast Iran

Background: The objective of this study was to determine the upper normal limit of serum alanine aminotransferase level in a population-based study in Golestan Province, northeast Iran. Methods: From the randomly invited individuals (2,292), 698 out of the 916 males and 1,351 out of the 1,376 females participated in the study (participation rate: 76.2 and 98.1, respectively). One hundred and twenty-one participants were excluded due to positive hepatitis B surface antigen or hepatitis C virus antibody and/or drinking more than 20 grams of alcohol per day. A total of 1,928 participants (1300 females) were included. The upper normal limit of serum alanine aminotransferase level was defined as the 95th percentile. Results: The upper normal limit of serum alanine aminotransferase level in normal weight and nondiabetics was significantly lower than the total study group (36 versus 45 U/L). Serum alanine aminotransferase level was independently associated with male gender, body mass index, and diabetes mellitus (OR=2.05; 95Cl: 1.44 - 2.94, OR=2.76; 95Cl: 1.84 - 4.13, and OR=2.96; 95Cl: 1.56-5.61, respectively). Conclusion: Considering the lower calculated upper normal limit in normal weight nondiabetic participants in this study, we recommend setting new upper normal limit for serum alanine aminotransferase level, It seems reasonable to set upper normal limit for serum alanine aminotransferase level in males and females separately

Optimal control of a large dam

A large dam model is an object of study of this paper. The parameters $L^{lower}$ and $L^{upper}$ are its lower and upper levels, $L=L^{upper}-L^{lower}$ is large, and if a current level of water is between these bounds, then the dam is assumed to be in normal state. Passage one or other bound leads to damage. Let $J_1$ $(J_2)$ denote the damage cost of crossing the lower (upper) level. It is assumed that input stream of water is described by a Poisson process, while the output stream is state-dependent (the exact formulation of the problem is given in the paper). Let $L_t$ denote the dam level at time $t$, and let $p_1=\lim_{t\to\infty}\mathbf{P}\{L_t= L^{lower}\}$, $p_2=\lim_{t\to\infty}\mathbf{P}\{L_t> L^{upper}\}$ exist. The long-run average cost $J=p_1J_1+p_2J_2$ is a performance measure. The aim of the paper is to choose the parameter of output stream (exactly specified in the paper) minimizing $J$.Comment: To appear in "Journal of Applied Probability" 44 (2007), No.

Population mechanisms of the green Er3+:LiYF4 laser

In computer simulations the mechanisms that lead to room-temperature continuous-wave green upconversion lasing in Er3+:LiYF4 are investigated. The rate-equation system considers the full erbium level scheme up to 2H9/2, ground-state depletion, excited-state absorption on the pump and laser wavelengths, three interionic processes, stimulated emission, and the crystal and resonator data of the experiments. Experimental results performed at the University of Hamburg, Germany, are reproduced in the simulation. The influence of different parameters as pump wavelength, absorption cross sections, interionic parameters, dopant concentration, and temperature is investigated. An avalanche effect which exploits the strong cross relaxation from the upper laser level and the upconversion from 4I13/2 leads to an efficient population of the upper laser level. At higher dopant concentrations the cross relaxation becomes detrimental to stimulated emission due to the depletion of the upper laser level. This concentration dependence can be considered as a general behavior of rare-earth-doped avalanche lasers