bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compression‐compression fatigue of selective electron beam melted cellular titanium (Ti‐6Al‐4V)
Authors: Hrabe Nikolas W. , Heinl Peter , Flinn Brian , Körner Carolin , Bordia Rajendra K. 
Published: September 2011

AbstractRegular 3D periodic porous Ti‐6Al‐4V structures intended to reduce the effects of stress shielding in load‐bearing bone replacement implants (e.g., hip stems) were fabricated over a range of relative densities (0.17–0.40) and pore sizes (∼500–1500 μm) using selective electron beam melting (EBM). Compression‐compression fatigue testing (15 Hz, R = 0.1) resulted in normalized fatigue strengths at 106 cycles ranging from 0.15 to 0.25, which is lower than the expected value of 0.4 for solid material of the same acicular α microstructure. The three possible reasons for this reduced fatigue lifetime are stress concentrations from closed porosity observed within struts, stress concentrations from observed strut surface features (sintered particles and texture lines), and microstructure (either acicular α or martensite) with less than optimal high‐cycle fatigue resistance. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Electrophoretic deposition of bioactive silica‐calcium phosphate nanocomposite on Ti‐6Al‐4V orthopedic implant
Authors: Aniket  , El‐Ghannam Ahmed 
Published: September 2011

AbstractBioactive silica‐calcium phosphate nanocomposite (SCPC) has been coated on Ti‐6Al‐4V implant employing an electrophoretic deposition (EPD) technique. The effects of composition and pH of the suspending medium on the zeta potential of three different SCPC formulations; SCPC25, SCPC50 and SCPC75 were analyzed. The average zeta potential of SCPC50 in pure ethanol was more negative than that of SCPC25 or SCPC75; however, the difference was not statistically significant. Discs of Ti‐6Al‐4V were passivated, coated with SCPC50 (200 nm–10 μm) and thermally treated at 600–800°C to produce a coating thickness in the range of 43.1 ± 5.7 to 30.1 ± 4.6 μm. After treatment at 600, 700, and 800°C, the adhesion strength at the SCPC50/Ti‐6Al‐4V interface was 42.6 ± 3.6, 44.7 ± 8.7, and 47.2 ± 4.3 MPa, respectively. SEM‐EDX analyses of SCPC50‐coated Ti‐6Al‐4V preimmersed in PBS for 7 days showed the formation of a Ca‐deficient hydroxyapatite surface layer. ICP‐OES analyses of the immersing solution (n = 6) showed an increase in the ionic concentration of Si from 3.3 ± 0.9 to 5.0 ± 1.2 ppm between days 1 and 4; after which no significant change in the Si concentration was measured. Bone marrow mesenchymal stem cells attached to the SCPC50‐coated implants expressed significantly higher (p < 0.05) alkaline phosphatase activity (82.4 ± 25.6 nmoles p‐NP/mg protein/min) than that expressed by cells attached to HA‐coated or uncoated implants. Results of the study suggest that bioactive SCPC50 can efficiently be coated on Ti‐6Al‐4V using EPD. The SCPC50 coating has the potential to enhance bone integration with the orthopedic implant. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Global Electric Circuit Parameters and their Variability Observed over Maitri, Antarctica
Authors: Jeeva K. , Panneerselvam C. , Nair K. U. , Selvaraj C. , Dhar Ajay , Pathan B. M. , Gurubaran S. 
Published: September 2011

Abstract
The global component of fairweather electricity is subject to special attention to watch the solar-terrestrial effects and secular changes in climate. It is generally considered that the diurnal variation of atmospheric electricity parameters, if they are not following the Carnegie pattern, are not representative of the global thunderstorm activity. Some of the results obtained from Maitri (70°45'54"S, 11°44'03"), are discussed here in context with global thunderstorm activity and space weather influences. The diurnal pattern of the Potential Gradient and current density strongly deviate from the Carnegie curve. We have showed that this deviation is not due to the local electrical influence but due to the global thunderstorm activity. During fairweather condition the parameters are representing the global thunderstorm activity and to some extent they respond to the upper atmospheric electro dynamic phenomenon. The mean value of the potential gradient (77.7 V/m) and current density (2.13 pA/m2) well below the expected global mean but close to the value reported from the same location and season in the past years. The mean conductivity, 3.34 x 10-14 mhom-1, is slightly at higher side and they exhibit a different diurnal trend comparing to the past measurements at this location.
Aerobic Capacity With Hybrid FES Rowing in Spinal Cord Injury: Comparison With Arms‐Only Exercise and Preliminary Findings With Regular Training
Authors: Taylor J. Andrew , Picard Glen , Widrick Jeffrey J. 
Published: September 2011

ObjectiveTo determine the magnitude and range of increases in peak aerobic capacity with hybrid–functional electrical stimulation (FES) rowing versus arms‐only rowing in persons with spinal cord injury.DesignComparison of graded exercise tests for peak responses during FES rowing and arms‐only rowing. Preliminary data on adaptations to FES row training were gathered in a subset of individuals.SettingOutpatient cardiovascular research laboratory.ParticipantsSix male patients with spinal cord injury (T4‐T9, American Spinal Injury Association class A).Methods or InterventionArms‐only rowing was compared with FES rowing, in which the person who is exercising synchronizes the voluntarily controlled upper body movement with the FES‐controlled leg movement via stimulation to the paralyzed leg muscles. A subgroup (n = 3) completed at least 6 months of a progressive FES row training exercise program with graded exercise tests every 6 months.Main Outcome MeasurementsPeak oxygen consumption, peak ventilation, peak respiratory exchange ratio, peak heart rate, and peak oxygen pulse.ResultsPeak oxygen consumption was greater during FES rowing than during arms‐only rowing (20.0 ± 1.9 mL/kg/min versus 15.7 ± 1.5 mL/kg/min, P = .01). Peak ventilation was similar, whereas peak respiratory exchange ratio and peak heart rate tended to be lower (P = .14 and P = .19, respectively). As a result, oxygen pulse was greater by 35% during FES rowing. Two of the three persons who completed at least 6 months of FES row training demonstrated increases in aerobic capacity greater than those previously observed in able‐bodied individuals.ConclusionsFES rowing may provide a more robust exercise stimulus for persons with spinal cord injury than most options currently available because of the greater aerobic demand.
Caregiver Ratings of Long‐term Executive Dysfunction and Attention Problems After Early Childhood Traumatic Brain Injury: Family Functioning Is Important
Authors: Kurowski Brad G. , Taylor H. Gerry , Yeates Keith Owen , Walz Nicolay C. , Stancin Terry , Wade Shari L. 
Published: September 2011

ObjectiveTo evaluate the relationship of family and parenting factors to long‐term executive dysfunction and attention problems after early childhood traumatic brain injury (TBI). We hypothesized that the magnitude of executive dysfunction and attention problems would be moderated by family and parenting factors.DesignA multicenter, prospective cohort study that included an orthopedic injury (OI) reference group.SettingThree tertiary academic children's hospital medical centers and one general medical center.ParticipantsChildren, ages 3‐7 years, hospitalized for OI, moderate TBI, or severe TBI.Methods and Outcome MeasurementsParental ratings of family functioning and parenting styles were obtained 18 months after the injury occurred. The main outcome measurements, which were parental ratings of children's executive function and attention, were performed at least 24 months after the injury occurred (mean, 39 months; range, 25‐63 months).AnalysisGroup comparisons were conducted with use of t‐tests, χ2 analysis, analysis of variance, and Pearson and Spearman correlations. Regression analysis was used to examine associations of the outcomes with family functioning and parenting styles and to test moderating effects of these factors on group differences.ResultsParticipants with severe TBI demonstrated increased executive dysfunction and attention problems compared with those who sustained moderate TBI or OI. Lower levels of family dysfunction were associated with better executive function and attention across groups but did not moderate group differences. However, attention deficits after severe TBI were exacerbated under conditions of more permissive parenting relative to attention deficits after OIs.ConclusionsExecutive function and attention problems persisted on a long‐term basis (>24 months) after early childhood TBI, and positive global family functioning and nonpermissive parenting were associated with better outcomes. Better characterization of the optimal family environment for recovery from early childhood TBI could help target future interventions.
Conceptualizing curriculum management in an effective secondary school: a Western Australian case study
Authors: Dimmock Clive , Wildy Helen 
Published: September 2011

ABSTRACTThis paper investigates the linkages between management processes and the curriculum using an academically effective secondary school as a case study. The aims of the study are twofold. First, in view of the acknowledged importance governments and others place on the quality of school leadership and management on the one hand and curriculum, teaching and learning reforms on the other, there is a need for empirical data as to how school leaders and managers work to secure improvements in curriculum, teaching and learning. This study purports to provide such data. The second aim acknowledges the need to develop conceptual frameworks and data collection instruments as aids to better understanding of complex relationships within school organizations.In order to achieve these aims, the investigation was structured around two guiding questions. The initial question centred on the roles and functions of school staff at each of three levels senior management, middle management and teacher ‐ in providing instructional leadership and curriculum management. The second guiding question concerned the ways in which school managers, particularly at the senior and middle management levels, influence and affect the processes and outcomes of teaching and learning. These questions lead to the postulate that a school experiencing high levels of academic effectiveness will be characterized by proactive school‐site management linking with, and supporting, teaching and learning. The objective was to clarify the perceptions, thoughts, understandings and behaviours of principals, middle managers and teachers by using a range of data collection methods which would yield thick descriptions of practice. One school was selected as a case‐study to allow for in‐depth analysis and the development of a research framework suitable for possible wider application in future.There are four main findings that can be drawn from the analysis. First, none of the senior managers is directly involved in curriculum management. Second, the principal and two deputy principals do play an indirect and important part in promoting academic performance by reinforcing school values in a wide variety of ways. Third, curriculum management is the responsibility of senior teachers and there is tight linkage between both senior teachers and teachers and high quality teaching and learning. Finally, the loose linkage between departments, and also between departments and senior management, provides little opportunity for a school‐wide approach to curriculum matters. It is evident that a whole‐school curriculum management perspective is absent in this school.
Evidence against the Relative Invariance of Timing in Handwriting
Authors: Wann John P. , Nimmo-Smith Ian 
Published: September 2011

Gentner (1987) has called into question the role of timing information in a number of motor behaviours. The status of an invariant relative timing model for handwriting, however, is still unclear, due to lack of previous studies that have applied appropriate tests to a suitable database. This study employs a direct application of the tests proposed by Gentner (1987) to handwriting samples collected from adult subjects, to ascertain whether an invariant temporal pattern was retained across changes in size and speed of writing. In line with Gentner's (1987) study of typing, the findings are strongly against the invariant relative timing model and bring into question motor program models that posit timing as an independent parameter.
Connectionism and the Learning of Probabilistic Concepts
Authors: Shanks David R. 
Published: September 2011

Three experiments examine the claim of Gluck and Bower (1986, 1988a, 1988b) that the learning of medical concepts can be simulated by a connectionist network in which the symptoms are the input and the diagnosis is the output. The first experiment replicates the main finding of Gluck and Bower. In this experiment, subjects were required to estimate the probability of each of two diseases, given a particular target symptom. In fact these two probabilities were identical, but because one illness was more common than the other, the target symptom was a better predictor of the rare disease than of the common disease. Contrary to a normative probability judgement account, subjects were biased in that they judged the probability of the rare disease given the target symptom to be greater than the probability of the common disease given the target symptom. Gluck and Bower argued that such a result was predicted by a connectionist network using the Rescorla-Wagner learning rule, but it is argued that Gluck and Bower's network simulation was not appropriate for the experiment they had performed. In fact, it appeared that the connectionist network failed to predict the bias in the subjects’ probability estimates. However, this conclusion rests on an assumption that Gluck and Bower implicitly made. They arranged for P(rare disease/target symptom) and P(com-mon disease/target symptom) to be identical across all trials on which the target symptom occurred, both on its own and with other symptoms present. Gluck and Bower assumed that the subjects were estimating these probabilities. But the results of the second experiment showed instead that the subjects were estimating the probability of each disease given only the target symptom. In the final experiment the design was changed so that this problem might be circumvented. In this experiment, again, the subjects were biased in their probability judgements exactly as the connectionist network predicted. Thus, finally, evidence was found which was compatible with the network model but not with a normative account, but this was true only if the network did not include a layer of hidden units.
A Dynamical Systems Approach to Skill Acquisition
Authors: Vereijken B. , Whiting H. T. A. , Beek W. J. 
Published: September 2011

This paper argues that the answer to the question, what has to be learned, needs to be established before the question, how is it learned, can be meaningfully addressed. Based on this conviction, some of the limitations of current and past research on skill acquisition are discussed. Motivated by the dynamical systems approach, the question of “what has to be learned” was tackled by setting up a non-linear mathematical model of the task (i.e. learning to make sideways movements on a ski apparatus). On the basis of this model, the phase lag between movements of the platform of the apparatus and the actions of the subject was isolated as an ensemble variable reflecting the timing of the subject in relation to the dynamics of the apparatus. This variable was subsequently used to study “how” the task was learned in a discovery learning experiment, in which predictions stemming from the model were tested and confirmed. Overall, these findings provided support for the hypothesis, formulated by Bernstein (1967), that one of the important effects of practice is learning to make use of reactive forces, thereby reducing the need for active muscular forces. In addition, the data from a previous learning experiment on the ski apparatus—the results of which had been equivocal—were reconsidered. The use of phase lag as a dependent variable provided a resolution of those findings. On the basis of the confirmatory testing of predictions stemming from the model and the clarification of findings from a previous experiment, it is argued that the dynamical systems approach put forward here provides a powerful method for pursuing issues in skill acquisition. Suggestions are made as to how this approach can be used to systematically pursue the questions that arise as a natural outcome of the experimental evidence presented here.
Human Reasoning: Deduction Rules or Mental Models, or Both?
Authors: Roberts Maxwell J. 
Published: September 2011

A good deal of energy is currently being expended into discovering the fundamental machinery underlying deductive reasoning. Is it based upon mental models (arrays) or deduction rules (propositions)? The appeal of finding a “grand unified theory” of reasoning is obvious, but the likelihood of achieving this must also be considered. This paper discusses the use of experimental psychology in attempts to discover the processes associated with the fundamental reasoning mechanism. One particular problem is that individuals can use different strategies to solve reasoning problems. The consequences of this are assessed in relation to: (1) the assumptions underlying the experiments, (2) the choice of tasks and task presentations intended to enable the fundamental reasoning processes to be viewed directly, and (3) the power status of the theories and the nature of the evidence required to show that either theory is superior. Under close scrutiny the debate appears to be unresolvable by using empirical techniques. However, although the main conclusions are negative, it is suggested that approaches that directly investigate individual differences are likely to be useful alternatives.
Information Relevance, Working Memory, and the Consideration of Alternatives
Authors: Mynatt Clifford R. , Doherty Michael E. , Dragan William 
Published: September 2011

People routinely focus on one hypothesis and avoid consideration of alternative hypotheses on problems requiring decisions between possible states of the world–-for example, on the “pseudodiagnosticity” task (Doherty, Mynatt, Tweney, & Schiavo, 1979). In order to account for behaviour on such “inference” problems, it is proposed that people can hold in working memory, and operate upon, but one alternative at a time, and that they have a bias to test the hypothesis they think true. In addition to being an ex post facto explanation of data selection in inference tasks, this conceptualization predicts that there are situations in which people will consider alternatives. These are: 1. “action” problems, where the alternatives are possible courses of action; 2. “inference” problems, in which evidence favours an alternative hypothesis. Experiment 1 tested the first prediction. Subjects were given action or inference problems, each with two alternatives and two items of data relevant to each alternative. They received probabilistic information about the relation between one datum and one alternative and picked one value from among the other three possible pairs of such relations. Two findings emerged; (1) a strong tendency to select information about only one alternative with inferences; and (2) a strong tendency, compared to inferences, to select information about both alternatives with actions. Experiment 2 tested the second prediction. It was predicted that data suggesting that one alternative was incorrect would lead many subjects to consider, and select information about, the other alternative. For actions, it was predicted that this manipulation would have no effect. Again the data were as predicted.
Effects of Age on the Ability to Remember Common and Rare Proper Names
Authors: Jones S.J. , Rabbitt P.M.A. 
Published: September 2011

Difficulties in remembering proper nouns increase with age. One factor is that names are arbitrary labels. Another is that because many people share the same names, mutual discriminability between names is less than than that between other words. Discriminability between names may reduce as the number of acquaintances increases. Also, most people have both a first and a second name. These have to be learned as a pair, but they may be of unequal distinctiveness and so be unequally well remembered. An experiment was designed to evaluate the relative effects of distinctiveness of first and second names on free and cued recall. Subjects (aged 60-69 or 70-79 years, matched on Mill-Hill vocabulary score) were asked to remember one of four lists of 16 names. Each was presented four times. The names were either common, rare, or a combination of the two–-a common first name with a rare surname, or vice versa. Subjects first freely recalled the names. They were next cued by either first name or surname to recall the remaining half of name pairs. Interactions between effects on recall of subjects’ ages and of the relative distinctiveness of first and second names provide partial support for a model incorporating “relative distinctiveness” as a factor in failures of name recall in old age.
The Internal Clock: Electroencephalographic Evidence for Oscillatory Processes Underlying Time Perception
Authors: Treisman Michel , Cook Norman , Naish Peter L. N. , MacCrone Janice K. 
Published: September 2011

It has been proposed that temporal perception and performance depend on a biological source of temporal information. A model for a temporal oscillator put forward by Treisman, Faulkner, Naish, and Brogan (1990) predicted that if intense sensory pulses (such as auditory clicks) were presented to subjects at suitable rates they would perturb the frequency at which the temporal oscillator runs and so cause over- or underestimation of time. The resulting pattern of interference between sensory pulse rates and time judgments would depend on the frequency of the temporal oscillator and so might allow that frequency to be estimated. Such interference patterns were found using auditory clicks and visual flicker (Treisman & Brogan, 1992; Treisman et al., 1990). The present study examines time estimation together with the simultaneously recorded electroencephalogram to examine whether evidence of such an interference pattern can be found in the EEG. Alternative models for the organization of a temporal system consisting of an oscillator or multiple oscillators are considered and predictions derived from them relating to the EEG. An experiment was run in which time intervals were presented for estimation, auditory clicks being given during those intervals, and the EEG was recorded concurrently. Analyses of the EEG revealed interactions between auditory click rates and certain EEG components which parallel the interference patterns previously found. The overall pattern of EEG results is interpreted as favouring a model for the organization of the temporal system in which sets of click-sensitive oscillators spaced at intervals of about 12.8 Hz contribute to the EEG spectrum. These are taken to represent a series of harmonically spaced distributions of oscillators involved in time-keeping.