Is a multiple excitation of a single atom equivalent to a single excitation of an ensemble of atoms?

Recent technological advances have enabled to isolate, control and measure the properties of a single atom, leading to the possibility to perform statistics on the behavior of single quantum systems. These experiments have enabled to check a question which was out of reach previously: Is the statistics of a repeatedly excitation of an atom N times equivalent to a single excitation of an ensemble of N atoms? We present a new method to analyze quantum measurements which leads to the postulation that the answer is most probably no. We discuss the merits of the analysis and its conclusion.Comment: 3 pages, 3 figure

Analysis of Maize Value Addition among Entrepreneurs in Taraba State, Nigeria

This study analyzed maize value addition among maize entrepreneurs in Taraba State, Nigeria. A multi-stage sampling procedure was used to collect primary data from two hundred and twelve respondents (212), using structured questionnaire. Data were analyzed using descriptive statistics, Value addition model, ANOVA, multinomial logistic regression, log likelihood test ratio and factor analysis. The result of the study revealed that most (62.3%) respondents were males. 61.3% were within the productive age of 21-40 years. Majority (71.1%) were married with household sizes of 6-10. The total of (32.8%) respondents of them had secondary school education, (46.6%) had processing experience of between 6-10 years in processing as their major occupation. proportionate (49.2%) of total respondents had non-farm income of N150,001 per annum. Results of the value addition analysis showed that maize processed as boiled maize is more profitable with a mean of N130, 900 per annum. The result from the multinomial logistic regression on choice of maize processing enterprises revealed that sex had negative coefficient, which implied that male respondents preferred grain production enterprise rather than processing into akamu, corn flour, massa and boiled maize. Also age had negative coefficient, implying that age increase tends to favour grain production than processing. In relation to processing constraints, the maize processing value chain was hampered by the following: inadequate processing facilities, inadequate credit/funds, high cost of transport and inadequate access to inputs. The study concluded that maize value addition is a profitable enterprise and entrepreneurs should be encouraged to venture into it. Also the Agricultural Development Project Programme should send extension agents to processors to encourage processing diversification especially into poultry feeds

Weak localization in disordered systems at the ballistic limit

The weak localization (WL) contribution to the two-level correlation function is calculated for two-dimensional disordered conductors. Our analysis extends to the nondiffusive (ballistic) regime, where the elastic mean path is of order of the size of the system. In this regime the structure factor (the Fourier transform of the two-point correlator) exhibits a singular behavior consisting of dips superimposed on a smooth positive background. The strongest dips appear at periods of the periodic orbits of the underlying clean system. Somewhat weaker singularities appear at times which are sums of periods of two such orbits. The results elucidate various aspects of the weak localization physics of ballistic chaotic systems.Comment: 13 pages, 13 figure

Utilizing hidden Markov processes as a tool for experimental physics

A hidden Markov process is a well-known concept in information theory and is used for a vast range of applications such as speech recognition and error correction. We bridge between two disciplines, experimental physics and advanced algorithms, and propose to use a physically oriented hidden Markov process as a new tool for analyzing experimental data. This tool enables one to extract valuable information on physical parameters of complex systems. We demonstrate the usefulness of this technique on low-dimensional electronic systems which exhibit time-dependent resistance noise. This method is expected to become a standard technique in experimental physics

Phytotoxicity and bioaccumulation of copper and chromium using barley (Hordeum vulgare L.) in spiked artificial and natural forest soils

The toxicities of two heavy metals, copper (Cu2+) and chromium (Cr6+), to barley (Hordeum vulgare L.) were evaluated using two types of substrates: artificial and natural forest soils. Phytotoxicity was assessed using a standardized toxicity test. Endpoints included plant emergence and shoot and root growth. Shoot and root concentrations of Cu and Cr were also measured. Data indicated that the root biomass was the most sensitive endpoint. The results showed that toxicity of Cr to root growth (IC50 = 6.6 mug/g in artificial soil; IC50 = 61.8 mug/g in forest soil) was higher than that of Cu (IC50 = 13.7 mug/g in artificial Soil; IC50 > 322 mug/g in forest soil). Data also indicated that the toxicity of Cu and Cr was significantly decreased in the spiked forest soil, suggesting lower metal bioavailability to barley in the natural soil. Analysis of tissue concentrations in barley showed that Cu and Cr were mainly accumulated in the roots. Toxicity was correlated with Cr residues in shoots (ltoreq 11.2 mug Cr/g and ltoreq 5.3 mug Cr/g for artificial and natural soils, respectively) and roots (ltoreq 161 mug Cr/g and ltoreq 51.7 mug Cr/g for artificial and natural soils, respectively) and Cu residues in roots (ltoreq 61.8 mug Cu/g and ltoreq 91.3 mug Cu/g for artificial and natural soils, respectively). Cu concentration in shoot tissues was ltoreq 61.8 mug Cu/g. Since it may overestimate toxicity, effect and risk assessment using spiked soils, particularly in artificial soil, must be used with diligence. Copyright 2003 National Research Council of Canada. Published by Elsevier Inc. All rights reserved.NRC publication: Ye

Persistent gender inequity in us undergraduate engineering: looking to Jordan and Malaysia for factors to their success in achieving gender parity

For more than three decades, the US federal government, industry and professional engineering societies has contributed millions of dollars to increase the number of women in US engineering programs with minimal impact. The research published on how to address the on-going United States (US) national challenge of increasing gender parity in undergraduate engineering programs is almost entirely US centric. The authors of this paper reached across borders and outside the STEM education literature to gain a different perspective on the US problem of persistent gender segregation in undergraduate engineering education. As we compared the issue of gender parity between the US, Jordan and Malaysia, three previously unexplored areas began to take shape: 1. The US has potentially inaccurately scoped the problem, 2. Different factors seem to contribute to greater gender equity in undergraduate engineering programs in Jordan and Malaysia than in the US, and 3. A sociological framework for analysis and interpretation (not previously published in the engineering education literature) helps us better understand the core causes of gender inequity in advanced industrialized countries, such as the US. Once we better understand the core causes, effective solutions can be designed. The purpose of this paper is to begin to re-scope the problem of increasing the number of women in engineering education in the US, identify potential factors that contribute to gender equity in Jordan and Malaysia, and to propose future areas of robust cross-national engineering education research