Toward practice-oriented theoretical models for internship training.

Internships accredited by the American Psychological Association are required to state a training model which guides their teaching and training of interns. Rodolfa, Kaslow, Stewart, Keilen, and Baker (2005) demonstrated that there is little correspondence between the models internships claim and their conceptualization and implementation of those models. Stedman, Hatch, Schoenfeld, and Keilen (2005) found that teaching during internship is primarily practice-oriented. Results of this study showed that the majority of internships self-identify as eclectic and offer psychotherapy training in fair correspondence to their eclectic models. These three studies suggest that more accurate training models for internships should be practitioner oriented and should reflect the eclectic nature of the majority of internships. Implications for revision of the accreditation standard and for internships' self-understanding are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dimensionless correlations for forced convection in liquid metals: Part II. two-phase flow

An experimental technique has been developed to study the convective heat-transfer characteristics of gas-agitated liquid metals. A sphere made from the same metal as the liquid metal under investigation is immersed in the center axis of the plume. The melting time of this sphere is detected, and from this time, the convective heat-transfer characteristics of the metal bath are deduced. Based on a variety of experimental results, a dimensionless correlation was deduced. This equation has the following form:

Vacuum distillation of liquid metals: Part II. Photographic study

Photographs of melt surface conditions and gas flows were taken during experiments which examined vacuum refining of melted steel scrap. The photographs illustrate the retarding effects of surface films on rates of copper and tin evaporation. The photographs also protray the characteristic variation in vapor flow pattern caused by altering chamber pressure. This was in agreement with the behavior predicted by the distillation model developed in Part I. It was also observed that vapor condensation may be a major problem area for industrial application of this process. Several solutions for this are suggested. W. G. DAVENPORT, formerly with McGill University     

The surface tension of liquid silver alloys: Part II. Ag−O alloys

The surface tensions of liquid Ag-O alloys have been determined by the sessile drop method. The surface activity of oxygen, as measured by ?(dσ/dX _O)X_O→0_j, where σ is the surface tension of the metal andX _O the mole fraction of oxygen, is quite large and equals 3.80×10⁵ dyne per cm at 980°C and 1.35×10⁵ dyne per cm at 1108°C. The heat of adsorption of oxygen is estimated to be of the order of 30 kcal per mole. Application of the monolayer approximation shows that liquid silver becomes saturated with oxygen when each adsorbed oxygen atom occupies an area of 33±5Ų. Small additions of platinum to silver do not change the characteristics of the adsorption of oxygen appreciably. An analysis of the data is consistent with the conclusion that saturation of the surface of liquid silver with oxygen results from the formation of an ionic two-dimensional compound at the surface. This hypothesis is tested in the case of several other systems and yields satisfactory results. The structure of these compounds is discussed. In the case of the Ag-O system, it appears to correspond to the stoichiometry Ag₃O.     

The modelling of equilibrium data for the liquid-liquid extraction of metals Part I. A survey of existing models

The various approaches which have been made to model equilibrium data for the extraction of metals in liquid-liquid systems have been reviewed. The limitations of any one model are highlighted. Those models based on the known chemistry of the process can be used with confidence to extrapolate data outside an experimentally measured region of the equilibria but models with as good an, if not better, accuracy can be based on a generalised polynomial and this method does not require a detailed chemical study to be made.     

Oligodendrogliomas. Part II: A new grading system based on morphological and imaging criteria

Myocardial perfusion scintigraphy is a noninvasive diagnostic method for the evaluation of patients with suspected or proven coronary artery disease (CAD). We utilized case-based reasoning (CBR) methods to develop the computer-based image interpretation system SCINA which automatically derives from a scintigraphic image data set an assessment concerning the presence of CAD. We compiled a case library of 100 patients who underwent both perfusion scintigraphy and coronary angiography to document or exclude the presence of CAD. The angiographic diagnosis of the retrieved nearest neighbor match of a scintigraphic input case was selected as the CBR diagnosis. We examined the effects of input data granularity, case indexing, similarity metric, and adaptation on the diagnostic accuracy of the CBR application SCINA. For the final prototype, sensitivity and specificity for detection of coronary heart disease were 98% and 70% suggesting that CBR systems may achieve a diagnostic accuracy that appears feasible for clinical use.     

Limited-sampling strategy models for itraconazole and hydroxy-itraconazole based on data from a bioequivalence study

We assessed the sedative potential of continuous infusions of remifentanil with a validated composite alertness scale in 160 patients (ASA physical status I or II) undergoing hip replacement surgery with spinal block (n = 61) or hand surgery using brachial plexus block (n = 93). They were randomized to receive one of the following initial dose regimens in double-blinded fashion: placebo or 0.04, 0.07, or 0.1 microg x kg(-1) x min(-1) remifentanil subsequently titrated to effect. Additional midazolam IV was allowed for adequate sedation as required. The combined analysis of both surgery groups revealed a dose-related increase in achievement of sedation level > or =2 within 15 min of the start of the study drug infusion; all remifentanil dose comparisons with placebo reached significance (P < 0.001). The remifentanil 50% effective dose for a composite sedation level > or =2 within 15 min of the start of drug infusion was estimated as 0.043 microg x kg(-1) x min(-1) (95% confidence interval 0.01, 0.059). The requirement for midazolam decreased with increasing remifentanil dose compared with placebo (P < 0.001). The median time to return to alertness after the end of infusion was 10-12 min in the remifentanil groups and 5 min in the placebo group. Significant incidences of nausea, pruritus, sweating, and respiratory depression were reported during remifentanil infusions compared with placebo. The data suggest that remifentanil may be useful for supplementation of regional anesthesia, provided that ventilation is carefully monitored. IMPLICATIONS: In this dose-finding, placebo-controlled study, remifentanil infusions were used to provide sedation during spinal and brachial plexus regional anesthesia. The 50% effective dose for achievement of sedation was 0.043 microg x kg(-1) x min(-1). Return to alertness occurred after 10-12 min (median time). Remifentanil infusions can be used to supplement regional anesthesia, but this requires careful monitoring of ventilation.     

Multiphase mixed-effects models for repeated measures data.

Behavior that develops in phases may exhibit distinctively different rates of change in one time period than in others. In this article, a mixed-effects model for a response that displays identifiable regimes is reviewed. An interesting component of the model is the change point. In substantive terms, the change point is the time when development switches from one phase to another. In a mixed-effects model, the change point can be a random coefficient. This possibility allows individuals to make the transition from one phase to another at different ages or after different lengths of time in treatment. Two examples are reviewed in detail, both of which can be estimated with software that is widely available. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Numerical models for casting solidification: Part II. Application of the boundary element method to solidification problems

A new numerical model, which is based on the boundary element method, was proposed for the simulation of solidification problems, and its application was demonstrated for solidification of metals in metal and sand molds. Comparisons were made between results from this model and those from the explicit finite difference method. Temperature recovery method was successfully adopted to estimate the liberation of latent heat of freezing in the boundary element method. A coupling method was proposed for problems in which the boundary condition of the interface consisting of inhomogeneous bodies is governed by Newton’s law of cooling in the boundary element method. It was concluded that the boundary element method which has several advantages, such as the wide variety of element shapes, simplicity of data preparation, and small CPU times, will find wide application as an alternative for finite difference or finite element methods, in the fields of solidification problems, especially for complex, three-dimensional geometries. On leave from Kyung-Pook National University, Taegu, Korea     

The omnipotent platelet. Part II: Further observations

General dental practitioners and community dental officers may need to consider several factors when referring patients to the consultant orthodontic service. In Birmingham, a local professional group incorporating representatives from both primary care and secondary care (consultant) services have drawn up a set of formal referral guidelines. The purpose of the exercise was to encourage the most appropriate use of the consultant service so that its resources could be directed towards those in greatest need. In this paper, the factors which determine the patients requiring referral are discussed; a second article will deal with the actual process of referral.     

Inclusion behavior and heat-transfer phenomena in steelmaking tundish operations: Part II. Mathematical model for liquid steel in tundishes

Fluid flow, heat transfer, and inclusion flotation have been modeled mathematically for several types of industrial tundish designs. Computations are presented to illustrate the importance of thermal natural convection currents in mixing the upper and lower layers of steel. The use of flow modification devices was shown to be reasonably effective in further reducing inclusion density levels at the intermediate to larger size ranges. Small inclusions (≦40 μm) were not readily removed with or without flow controls because of their low Stokes rising velocities. Formerly Doctoral Candidate Formerly Postdoctoral Fellow, Department of Mining and Metallurgical Engineering, McGill Metals Processing Centre, McGill University. Macdonald Professor of Metallurgy     

Wetting of ceramic particulates with liquid aluminum alloys: Part II. Study of wettability

Wetting phenomena in ceramic particulate/liquid Al-alloy systems were investigated experimentally using a new pressure infiltration technique developed by the authors. Studies were performed on two different ceramic particulates, SiC and B₄C, with four different liquid aluminum alloy matrices, pure Al, Al-Cu, Al-Si, and Al-Mg. Five major variables tested to study wetting phenomena in ceramic/Al-alloy systems were holding time, melt temperature, alloying element, gas atmosphere, and particulate. Metal: ceramic interfaces were investigated with optical microscopy, SEM, EPMA, and Auger Electron Spectroscopy (AES) in order to understand better the wetting process. The threshold infiltration pressure decreased with, temperature as well as with pressurization time for all the ceramic/metal systems. A strong correlation was found between the alloying effect on the threshold pressure and the free energy of formation of oxide phase of the alloying element. More reactive alloying elements were more effective in improving wettability. In air atmospheres, the threshold pressure usually increased markedly as a result of a thick oxide layer formation on the liquid front. Compacts of B₄C particulates showed lower threshold pressures than those of SiC, particulates. Fracture occurred in a generally brittle manner in infiltrated SiC, specimens. AES element profiles on the fracture surfaces showed fast diffusion of Si, and pile-up of C at the metal∶SiC boundaries which promoted fracture through the carbon-rich layer. The fracture surfaces of infiltrated B₄C specimens indicated plastic deformation, hence a more ductile failure mode.     

Measurement of magnitude and direction of velocity in high-temperature liquid metals. Part II: Experimental measurements

Experimental research work on the application of the sphere melting technique to measure magnitude as well as direction of velocity in liquid metals is the focus of Part II of this series of articles. The sphere melting time is detected by means of a sensing wire, which is connected to a specially designed electrical circuit. A novel apparatus is used whereby liquid metal is rotated with a specified tangential velocity. To measure the magnitude of velocity, the sensing wire of the sphere melting is located at the center of the sphere. To detect the direction of flow, three sensing wires are employed. These wires are placed at strategic locations inside the sphere and detect the melting times at three different locations. The ratio of the melting times of these locations identifies the direction of the flow. The experimental results are compared against model predictions. In addition, an error analysis is carried out to discover the possible sources of error in the detection of metal velocity. The liquid metals used in this research work are commercial purity aluminum and AZ91 magnesium alloy.     

The modified quasi-chemical model: Part II. Multicomponent solutions

Further improvements to the modified quasi-chemical model in the pair approximation for shortrange ordering (SRO) in liquids are extended to multicomponent solutions. The energy of pair formation may be expanded in terms of the pair fractions or in terms of the component fractions, and coordination numbers are permitted to vary with composition. The model permits complete freedom of choice to treat any ternary subsystem with a symmetric or an asymmetric model. An improved general functional form for “ternary terms” in the excess Gibbs energy expression is proposed. These terms are related to the effect of a third component upon the binary pair interaction energies. It is shown how binary subsystems that have been optimized with the quasi-chemical model can be combined in the same multicomponent Gibbs energy equation with binary subsystems that have been optimized with a random-mixing Bragg-Williams model and a polynomial expression for the excess Gibbs energy. This is of much practical importance in the development of large databases for multicomponent solutions. The model also applies to SRO in solid solutions as a special case, when the number of lattice sites and coordination numbers are constant.     

The interfacial kinetics of the reaction of CO2 with nickel: Part II. the decarburization of liquid nickel

The kinetics of decarburization of liquid nickel in CO₂-CO mixtures have been studied at 1400 and 1500°C, using the experimental arrangement of the impinging jet. At carbon concentrations above about 1 wt pct, pressures of CO₂ ⪯ 0.1 atm, and for total gas flow-rates above about 40 l/min (STP) impinging on a metal surface of 2.08 cm², it is concluded that the interfacial reaction step controls the rate. Comparison with isotope exchange studies indicates that dissociative chemisorption of CO₂ is the rate determining step. Rate constants, based on the nominal surface area, are 1.2 ×10⁻³ and 1.4 × 10⁻³ mol/cm² · s · atm at 1400 and 1500°C, respectively. on leave of absence from the Homer Research Laboratories of the Bethlehem Steel Co.     

A non-invasive technique for 3-dimensional assessment of articular cartilage thickness based on MRI. Part 2: Validation using CT arthrography

Established methods for the measurement of articular cartilage thickness are invasive and cannot be sequentially applied in living subjects. In the present study, the distribution of cartilage thickness throughout entire joint surfaces was determined from MR images obtained with a fat-suppressed gradient-echo sequence at a resolution of 0.31 x 0.31 x 2.00 mm3, and compared to that derived from CT arthrography. A minimal distance algorithm was employed to produce 3D cartilage thickness maps of seven cadaveric human knee joints. The mean amount of deviation of the cartilage volumes was 5.6% (+/- 4.6), statistical analysis showing that there was high agreement between the two methods (r = 0.995, slope = 1.037, y-intercept = -90.5 mm3). The 3D thickness maps yielded a striking agreement between the two methods, the maximum values generally yielding a deviation of none or one thickness interval of 0.5 mm. This investigation shows that accurate 3D assessment of articular cartilage thickness can be performed with MRI, this technique having the advantage that it is suitable for investigating living subjects.     

The Chinese total diet study in 1990. Part II. Nutrients

This paper reports the intakes of 72 nutrients and their dietary sources obtained from the Chinese total diet study in 1990. Most of the nutrient intakes are close or equal to their corresponding recommended daily allowances (RDAs). Both the total energy intake (2203 kcal) and the proportions contributed by protein, fat, and carbohydrate meet the current Chinese RDAs and the World Health Organization (WHO) nutrient goals. The average protein intake was 64 g/day. The intake of essential amino acids all exceeded the Chinese RDA, and their proportions were generally consistent with the WHO recommended pattern. The average fat intake was 51.2 g/day (21.2% of the total energy intake). However, the dietary fat intake has been increasing significantly in the Chinese diet and the proportion of animal fat has reached 53% of the total fat intake. The total saturated:total monounsaturated: total polyunsaturated fatty acid ratio was 1.0:1.5:1.0. Although the average cholesterol intake was only 179 mg/day, it was 248 mg/day in the South 1 region. The intakes of thiamine and riboflavin were below the RDA. Retinol intakes in all the 4 regions were low. Most (80%) of the retinol (equivalent) intakes were from carotenoids. The average intake of total tocopherol was 89% of the RDA, and among the 4 regions, only the South 2 region has relatively low intake. The intakes of iron, copper, manganese, sodium, and phosphorus were adequate. The intakes of calcium, zinc, and potassium were insufficient, and intakes of selenium and magnesium were a little low. High sodium and low potassium intake is a traditional problem in the Chinese diet.     

The effect of abdominal wall morphology on ultrasonic pulse distortion. Part II. Simulations

Wavefront propagation through the abdominal wall was simulated using a finite-difference time-domain implementation of the linearized wave propagation equations for a lossless, inhomogeneous, two-dimensional fluid as well as a simplified straight-ray model for a two-dimensional absorbing medium. Scanned images of six human abdominal wall cross sections provided the data for the propagation media in the simulations. The images were mapped into regions of fat, muscle, and connective tissue, each of which was assigned uniform sound speed, density, and absorption values. Propagation was simulated through each whole specimen as well as through each fat layer and muscle layer individually. Wavefronts computed by the finite-difference method contained arrival time, energy level, and wave shape distortion similar to that in measurements. Straight-ray simulations produced arrival time fluctuations similar to measurements but produced much smaller energy level fluctuations. These simulations confirm that both fat and muscle produce significant wavefront distortion and that distortion produced by fat sections differs from that produced by muscle sections. Spatial correlation of distortion with tissue composition suggests that most major arrival time fluctuations are caused by propagation through large-scale inhomogeneities such as fatty regions within muscle layers, while most amplitude and waveform variations are the result of scattering from smaller inhomogeneities such as septa within the subcutaneous fat. Additional finite-difference simulations performed using uniform-layer models of the abdominal wall indicate that wavefront distortion is primarily caused by tissue structures and inhomogeneities rather than by refraction at layer interfaces or by variations in layer thicknesses.