Ethnocultural factors and substance abuse: Toward culturally sensitive treatment models.

Discusses the role of ethnocultural factors in understanding and treating substance abuse disorders. Research and theory suggest that acculturation experiences, sources of stress, coping mechanisms, social support variations, and beliefs about substance use are key factors associated with differential patterns of substance abuse among some ethnic groups, particularly African Americans, Hispanics, and Native Americans. In recent years, models of substance abuse intervention specifically targeting these ethnic groups have been developed. The author examines the movement toward culturally sensitive psychosocial treatment models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

THE RECURSIVE FITTING OF SUBSET VARX MODELS

Abstract. A vector time series model of the form A(L)y(t) + B(L)x(t) =ε(t) is known as a vector autoregressive model with exogenous variables (VARX model) and involves a regressand vector y(t) and a regressor vector x(t). This paper provides a method for the recursive fitting of subset VARX models. It suggests the use of ascending recursions in conjunction with an order selection criterion to choose an 'optimum' subset VARX model.     

Selecting the forgetting factor in subset autoregressive modelling

Abstract. Conventional methods to determine the forgetting factors in autoregressive (AR) models are mostly based on arbitrary or personal choices. In this paper, we present two procedures which can be used to select the forgetting factor in subset AR modelling. The first procedure uses the bootstrap to determine the value of a fixed forgetting factor. The second procedure starts from this base and applies the time-recursive maximum likelihood estimation to a variable forgetting factor. In one illustration using real exchange rates, we demonstrate the effect of the forgetting factor in subset AR modelling on ex ante forecasting of non-stationary time series. In a second illustration, these two procedures are applied to time-update forecasts for a stock market index. Subset AR models not including a forgetting factor act as a set of benchmarks for assessing ex ante forecasting performance, and consistently improved forecasting performance is demonstrated for these proposed procedures.     

PROJECTION MODULUS: A NEW DIRECTION FOR SELECTING SUBSET AUTOREGRESSIVE MODELS

Selecting a parsimonious subset autoregressive time series model is a valuable objective particularly where there is or may be evidence that a time series may have some form of periodic or quasi-periodic behaviour. An efficient model selection procedure is essential because of the large number of possible alternative models involved. The explanation of an increase in residual variance due to excluding a lag is examined in Hilbert space. As a result, a new statistic, the projection modulus , and its derivatives are developed to assess the significance of any lag in a model. The impact of deleting a lag, as measured by these statistics, helps to produce a selection procedure where true lags have less chance of being removed. We then assess an efficient subset autoregressive model selection procedure employing these statistics. The success of the proposed procedure is illustrated by its efficiency in identifying the true model for simulated and real data.     

Effect of Reciprocation Frequency on Friction and Wear of Vibrating Contacts Lubricated with Soybean-Based B100 Biodiesel

The use of renewable, bio-based fuels has become increasingly widespread in recent years, with a major example being biodiesel, a bio-derived alternative to Number 2 diesel fuel. The increased usage of biodiesel gives rise to an augmented need to understand its tribological effects on critical engine components. This study focused on determining the tribological performance of soybean-based B100 (i.e., pure) biodiesel within a fuel injector with varying oscillating frequency by performing a series of linear reciprocating tribological tests of biodiesel-lubricated interfaces with varying reciprocating frequency. Comparison of friction coefficient variation with reciprocating frequency indicated a transition from boundary lubrication to hydrodynamic lubrication as the frequency increased, while hysteresis loop and energy loss observations showed a transition between full stick and partial slip contact with increasing frequency. However, observations of induced wear showed the wear to increase with increasing frequency, most likely due to the augmented number of sliding cycles as well as an increased degree of interfacial slip.     

Characteristics of Bi-metallic Interfaces Formed During Direct Energy Deposition Additive Manufacturing Processing

Metallurgical and Materials Transactions B - Various additive manufacturing processes are being evaluated to reduce the time and cost for fabrication of low volume, complex, and multifunctional...     

Systems integration with reliability in mind

Device sophistication and data-processing ability continue to grow steadily and new processing devices dedicated to special functions such as speech processing or data encryption are regularly being introduced or replaced by more powerful devices. As device manufacturers extend the power and applicability of devices, new system design concepts are needed. Not only are specialist disciplines required but also the question of integration arises, a problem, all too easily overlooked. This paper looks at the problems caused by increased complexity (such as in two-sided cards on buses) and puts forward suggestions as to how to improve reliability, such as protecting the system clock and limiting the amount of parallel I/O, at least on the system card.     

Integrated fuel-cycle models for fast breeder reactors

Breeder-reactor fuel-cycle analysis can be divided into four different areas or categories. The first category concerns questions about the spatial variation of the fuel composition for single loading intervals. Questions of the variations in the fuel composition over several cycles represent a second category. Third, there is a need for a determination of the breeding capability of the reactor. The fourth category concerns the investigation of breeding and long-term fuel logistics. Two fuel-cycle models used to answer questions in the third and fourth area are presented.The space- and time-dependent actinide balance, coupled with criticality and fuel-management constraints, is the basis for both the Discontinuous Integrated Fuel-Cycle Model and the Continuous Integrated Fuel-Cycle Model. These models are derived by formally condensing the base equations through spatial integration. Cycle-average isotopic microscopic reaction rate and reactivity-worth coefficients, based on equilibrium behavior, complete the derivation of the discontinuous model. Approximating the discontinuous reload with continuous charge and discharge currents transforms the discontinuous model into the more mathematically elegant continuous model.The results of the continuous model are compared with results obtained from detailed two-dimensional space and multigroup depletion calculations. The continuous model yields nearly the same results as the detailed calculation, and this is with a comparatively insignificant fraction of the computational effort needed for the detailed calculation. Thus, the integrated model presented is an accurate tool for answering questions concerning reactor breeding capability and long-term fuel logistics.     

Effects of type of social reinforcement on the intelligence performance of lower-class Black children.

Examined the effects of different types of reinforcement on the performance of 80 Black 2nd grade males on the WISC-R. Ss given candy or culturally relevant social reinforcement obtained significantly higher scores than Ss given either no reinforcement or traditional social reinforcement. (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimation of particle volume fraction, mass fraction and number density in thermophoretic deposition systems

A method is presented to predict the soot volume fraction in soot-laden gas streams in systems where thermophoresis is the dominant mechanism of particle deposition onto adjoining surfaces. In particular, we considered deposition of silica particles on a circular cylinder in cross-flow to a premix CH₄/O₂ flame, a setup similar to the one used in the outside vapor deposition process used for making optical fibers. Silica particles were produced by introducing SiCl₄ along with the premix gases to the burner and were collected on a cylinder. Heat flux and mass deposition rate measurements on the cylinder were performed and recorded as a function of time. Considering thermophoresis to be the dominant mechanism of particle deposition, a simple theory was developed to establish the relationship between the measured quantities. The theory predicted that the thickness at any given time t was expected to increase linearly with the integral of (integrated from t=0 to t=t), where q^′′(t) is the heat flux. Such a linear relationship was observed for five different reactant flow rates confirming thermophoresis to be the dominant mechanism of particle deposition. Soot volume fraction and soot mass fraction were calculated from the slope of these linear fits and were seen to be in good agreement with the estimates of the soot fraction from light scattering measurements. Based on the light scattering estimates of particle diameter, particle number densities were also estimated.