Shouldering in B diffusion profiles in Si: Role of di-boron diffusion

The role of di-boron diffusion in evolution of B diffusion profiles has been investigated. We find that boron pair (B-s-B-i) diffusion can become as important as boron-interstitial pair (B-s-Si-i) diffusion when both boron concentration and annealing temperature are very high, leading to concentration-dependent B diffusion. Our simulated B diffusion profiles with dramatic shouldering are in excellent agreement with experimental ones reported by Schroer [Appl. Phys. Lett. 74, 3996 (1999)] for high-temperature (approximate to 1200 degrees C) postimplantion annealing of ultralow-energy (approximate to500 eV) implanted high-concentration (>10(19) cm(-3)) boron in silicon

Catalytic role of boron atoms in self-interstitial clustering in Si

Using density functional theory (DFT) calculations and kinetic simulations, we have investigated the influence of boron atoms on self-interstitial clustering in Si. From DFT calculations of neutral interstitial clusters with a single B atom (BsIn, nIn–1 + BsI) becomes substantially weaker than that of an interstitial (BsIn-->BsIn–1 + I) when n>=4. This implies boron can be liberated while leaving an interstitial cluster behind. Our kinetic simulations including the boron liberation explain well experimental observations reported by J. L. Benton et al., J. Appl. Phys. 82, 120 (1997)

Computational Study of Copper(II) Complexation and Hydrolysis in Aqueous Solutions Using Mixed Cluster/Continuum Models

We use density functional theory (B3LYP) and the COSMO continuum solvent model to characterize the structure and stability of the hydrated Cu(II) complexes [Cu(MeNH_2)(H_2O)_(n−1)]^(2+) and [Cu(OH)_x(H_2O)_(n−x)]^(2−x) (x = 1−3) as a function of metal coordination number (4−6) and cluster size (n = 4−8, 18). The small clusters with n = 4−8 are found to be the most stable in the nearly square-planar four-coordinate configuration, except for [Cu(OH)_3(H_2O)]^−, which is three-coordinate. In the presence of the two full hydration shells (n = 18), however, the five-coordinate square-pyramidal geometry is the most favorable for Cu(MeNH_2)^(2+) (5, 6) and Cu(OH)^+ (5, 4, 6), and the four-coordinate geometry is the most stable for Cu(OH)_2 (4, 5) and Cu(OH)_3^− (4). (Other possible coordination numbers for these complexes in the aqueous phase are shown in parentheses.) A small energetic difference between these structures (0.23−2.65 kcal/mol) suggests that complexes with different coordination numbers may coexist in solution. Using two full hydration shells around the Cu^(2+) ion (18 ligands) gives Gibbs free energies of aqueous reactions that are in excellent agreement with experiment. The mean unsigned error is 0.7 kcal/mol for the three consecutive hydrolysis steps of Cu^(2+) and the complexation of Cu^(2+) with methylamine. Conversely, calculations for the complexes with only one coordination shell (four equatorial ligands) lead to a mean unsigned error that is >6.0 kcal/mol. Thus, the explicit treatment of the first and the second shells is critical for the accurate prediction of structural and thermodynamic properties of Cu(II) species in aqueous solution

Comparing Predictors of Diet Quality in Canada Over Time Under Consideration of Altering Food Guides

Latest data on the diet of Canadians from the Canadian Community Health Survey reveals that the diet quality of Canadians needs improvement. Within this paper predictors of diet quality in Canada are identified based on two cross-sectional data sets from the Canadian Food Expenditure Survey. To measure diet quality, the Canadian Healthy Food Diversity (CanHFD)-Index is developed which is based on Food Guide recommendations. Moreover, this paper considers that the Food Guide between survey years has changed when analyzing diet quality. To track changes in demand for diet quality we use “Canada’s Food Guide 1982” to calculate CanHFD-Index for 1984 and 1996. Changes in demand for diet quality according to “Canada’s Food Guide to Healthy Eating 1992” are observed by calculating CanHFD-Index with data from 1984 and 1996. Theoretically, this model is related to Becker’s household production theory and Lancaster’s characteristics approach. Multiple regression results show significant changes in the Canadian demand for food diversity over time. Some of the differences can be traced back to the different versions of the Canada Food Guide. Increasing age, higher income, being female, and high education level are positive predictors of diet quality in 1984 and 1996 among others.diet quality, healthy food diversity, Canada, Food Guides, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Health Economics and Policy, D12, D13, I12, Q18,

OBSERVING CHANGES IN CANADIAN DEMAND FOR FOOD DIVERSITY OVER TIME

Research on food diversity is interdisciplinary in nature, and is highly relevant for different research fields. Eating a variety of foods has been linked to the nutritional well-being of the household. From an economic perspective, food diversity can be used to derive important conclusions regarding the economic well-being of a population under study. This paper attempts to fill two main research gaps. The first objective of this paper is to analyze the demand for food diversity in Canada for the first time. This includes observing the extent of food diversity and the identification of respective socio-economic determinants. The second main objective is to compare changes in the cross-sectional demand for food diversity over time using three data sets of the Canadian Food Expenditure Survey (1984, 1996 and 2001). Food diversity is measured twice, with a measure used in nutritional studies and an economic diversity measure to draw conclusions for both research fields. Results show that in all years the demand for diversity (both indices) is positively influenced by income, age, and household size. We observe a significant quadratic influence of income in all models. Over all years, males and singles have a lower demand for food diversity than females and married Canadians. In addition, the region the household lives in is a strong predictor of food diversity. We observe changes in demand for food diversity in Canada. It is shown that the demand for food diversity decreased from 1984 to 1996 and 2001.Demand and Price Analysis, Food Consumption/Nutrition/Food Safety,

PAMAM Dendrimers Undergo pH Responsive Conformational Changes without Swelling

Atomistic molecular dynamics (MD) simulations of a G4-NH2 PAMAM dendrimer were carried out in aqueous solution using explicit water molecules and counterions (with the Dreiding III force field optimized using quantum mechanics). Our simulations predict that the radius of gyration (R_g) of the dendrimer changes little with pH from 21.1 Å at pH 10 (uncharged PAMAM) to 22.1 Å at pH 5 (charged with 126 protons), which agrees quantitatively with recent small angle neutron scattering (SANS) experiments (from 21.4 Å at pH 10 to 21.5 Å at pH 5). Even so we predict a dramatic change in the conformation. The ion pairing in the low pH form leads to a locally compact dense shell with an internal surface area only 37% of the high pH form with a dense core. This transformation from “dense core” at high pH to “dense shell” at low pH could facilitate the encapsulation and release of guest molecules (e.g., drugs) using pH as the trigger, making dendrimers a unique drug delivery vehicle

Electromagnetic field application to underground power cable detection

Before commencing excavation or other work where power or other cables may be buried, it is important to determine the location of cables to ensure that they are not damaged. This paper describes a method of power-cable detection and location that uses measurements of the magnetic field produced by the currents in the cable, and presents the results of tests performed to evaluate the method. The cable detection and location program works by comparing the measured magnetic field signal with values predicted using a simple numerical model of the cable. Search coils are used as magnetic field sensors, and a measurement system is setup to measure the magnetic field of an underground power cable at a number of points above the ground so that it can detect the presence of an underground power cable and estimate its position. Experimental investigations were carried out using a model and under real site test conditions. The results show that the measurement system and cable location method give a reasonable prediction for the position of the target cable

A Drama-Based Group Intervention for Adolescents to Improve Mentalization

This dissertation is an innovative intervention design to improve mentalization in preadolescents. The intervention presented is conducted in a group format and using techniques drawn from drama-based therapy. I have provided a brief literature review on mentalization, and relevant topics in group treatment and drama therapy. I have outlined key concepts from mentalization theory including: (a) the development of the self, (b) its relationship to attachment, (c) psychic equivalence and pretend mode functioning, (d) marked-affect mirroring, (e) the various facets of mentalization, and (f) mentalization treatment with children. After outlining these concepts, I discuss psychodynamic group treatment, mentalization-based group therapy, and the mechanism of change in group treatment from a neurobiologically informed perspective. From there I discuss concepts from play and drama therapy relevant to work with preadolescents. The topics covered in the literature review are used as a basis for an mentalization-based intervention appropriate for preadolescents. The argument is made that drama therapy is an appropriate vehicle through which this age group can be engaged as they are often regarded as too old for the typical toys of play therapy, but not yet ready for an adult approach to group treatment. Following the literature review, an intervention design is proposed. The proposal offers guidance on the structure of the group intervention, approach taken by the therapist, and the format of a typical session. Finally, limitations, future directions, and reflections on conducting this research are discussed

Detection and Location of Underground Power Cable using Magnetic Field Technologies

The location of buried underground electricity cables is becoming a major engineering and social issue worldwide. Records of utility locations are relatively scant, and even when records are available, they almost always refer to positions relative to ground-level physical features that may no longer exist or that may have been moved or altered. The lack of accurate positioning records of existing services can cause engineering and construction delays and safety hazards when new construction, repairs, or upgrades are necessary. Hitting unknown underground obstructions has the potential to cause property damage, injuries and, even deaths. Thus, before commencing excavation or other work where power or other cables may be buried, it is important to determine the location of the cables to ensure that they are not damaged during the work. This paper describes the use of an array of passive magnetic sensors (induction coils) together with signal processing techniques to detect and locate underground power cables. The array consists of seven identical coils mounted on a support frame; one of these coils was previously tested under laboratory conditions, and relevant results have been published in [1]. A measurement system was constructed that uses a battery powered data acquisition system with two NI 9239 modules connected to the coil array, and controlled by a laptop. The system is designed to measure the magnetic field of an underground power cable at a number of points above the ground. A 3 by 3 m test area was chosen in one of our campus car parks. This area was chosen because the university’s utility map shows an isolated power cable there. Measurements were taken with the array in 16 different test positions, and compared with the values predicted for a long straight horizontal cable at various positions. Finally, error maps were plotted for different Z-coordinate values, showing the minimum fitting error for each position in this plane. One such map is shown in Figure 1; the low error values of 4-5% give a high degree of confidence that most of the measured signal is due to a cable near to these positions. This view is supported by the fact that the university’s utility map shows the cable at X = 1.4 m, and by amplitude measurements taken with a hand-held magnetic field meter