Gait adaptations before and after anterior cruciate ligament reconstruction surgery

Gait analyses of rehabilitated individuals with anterior cruciate ligament (ACL) deficiency and reconstruction have identified the final adaptations of increased hip extensor torque and hamstring electromyography (EMG) and decreased knee extensor torque and quadriceps EMG during stance. The initial adaptations to injury and surgery are, however, unknown as are the factors that influence the development of the adaptations. Identification of the initial response to injury would provide a basis for determining whether the final adaptations are learned automatically or if they are the result of a lengthy training period in which various factors may affect their development. The purpose of the study was to evaluate the initial effects of ACL injury and reconstruction surgery on joint kinematics, kinetics, and energetics, during walking. Injured limbs from nine subjects with ACL injury were tested 2 wk after injury, and 3 and 5 wk after surgery. Ten healthy subjects were tested. Kinematic and ground reaction data were collected and combined with inverse dynamics to calculate the joint torques and powers. A knee extensor torque throughout most of stance was observed in the injured limbs at all test sessions. This result was in conflict with previous observations of reduced extensor torque or a flexor torque in rehabilitated patients with ACL reconstruction and patients with ACL deficiency. This result also differed from the typical midstance extensor then flexor torque in healthy control subjects. Trend analysis showed a significant (P < 0.001) change in average position at the hip and knee, extensor angular impulse at the hip, and positive work done at the hip 3 wk after surgery followed by a partial rehabilitation at 5 wk after surgery. Power and work produced at the knee were reduced fivefold (P < 0.001) after 5 wk of rehabilitation and did not recover to pre-surgical levels. The existence of a long-lasting knee extensor torque 2 wk after injury indicated that the adaptation process to ACL deficiency is lengthy, requiring many gait cycles, and that numerous factors could be involved in learning the adaptations.     

Predicting recidivism with the Psychopathy Checklist: Are factor score composites really necessary?

In two previous studies on general and violent recidivism (Walters & Heilbrun, 2010; Walters, Knight, Grann, & Dahle, 2008), the summed composite antisocial facet of the Psychopathy Checklist displayed incremental validity relative to the other 3 facets (interpersonal, affective, lifestyle), whereas the other 3 facets generally failed to demonstrate incremental validity relative to the antisocial facet. Because summed composite scores do not account for ordinal item distributions, the 6 Walters et al. (2008) samples were reanalyzed with factor score composites derived from a 4-factor confirmatory factor analysis. The results, however, showed little change from what had been obtained earlier with summed composite scores. Two additional samples not previously included in any incremental validity analyses of the Psychopathy Checklist evidenced a 3-factor structure, with the lifestyle and antisocial facets merged into a single factor. This single factor displayed incremental validity relative to the interpersonal and affective facets, but the reverse was not true regardless of whether summed composite scores or factor score composites were used. A comparison of zero-order correlations from all 8 samples revealed that the antisocial summed composite score predicted significantly better than the summed composite scores for the other 3 facets and that a superordinate factor failed to improve on the performance of either the antisocial summed composite score or the antisocial factor score composite. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Probabilistic GRASP-Tabu Search algorithms for the UBQP problem

This paper presents two algorithms combining GRASP and Tabu Search for solving the Unconstrained Binary Quadratic Programming (UBQP) problem. We first propose a simple GRASP-Tabu Search algorithm working with a single solution and then reinforce it by introducing a population management strategy. Both algorithms are based on a dedicated randomized greedy construction heuristic and a tabu search procedure. We show extensive computational results on two sets of 31 large random UBQP instances and one set of 54 structured instances derived from the MaxCut problem. Comparisons with state-of-the-art algorithms demonstrate the efficacy of our proposed algorithms in terms of both solution quality and computational efficiency. It is noteworthy that the reinforced GRASP-Tabu Search algorithm is able to improve the previous best known results for 19 MaxCut instances.     

Craft Training Issues in American Industrial and Commercial Construction

The construction industry relies on skilled craft workers supplied through various training programs. Based on a nationwide survey of industry experts regarding craft training programs, this paper examines the current state and effectiveness of construction craft training via 93 respondents from a wide range of U.S. industrial and commercial construction firms and associated craft training centers. The study’s survey data allowed the writers to examine the major issues regarding craft training, such as the relative importance of basic core topics, training completion rates, the relation between trades’ engagement and training, and the barriers of advancing craft training in construction. The paper also uses the experts’ responses to estimate the benefits of craft training on productivity, turnover, absenteeism, safety, and rework. Various statistical methods are used to support the analysis. Problems are identified in craft training among the training programs examined and potential solutions for improving craft training effectiveness are suggested.     

A conserved mitotic kinase active at late anaphase-telophase in syncytial Drosophila embryos

Mutations in the Drosophila gene polo cause abnormal mitotic and meiotic divisions. This gene encodes a 577-amino-acid protein that has an N-terminal putative kinase domain and a 300-residue C-terminal domain. In budding yeast, a homologous kinase is encoded by CDC5 (ref. 3), a gene required for nuclear division late in the mitotic cycle and during meiosis. Murine homologues have also been described. Here we show that the polo gene product immunoprecipitated from extracts of single Drosophila embryos can phosphorylate casein in vitro, and that the kinase activity peaks cyclically at late anaphase/telophase. This contrasts with the cyclical activity of cyclin B-associated p34cdc2 kinase, which is maximal upon entry into mitosis during the rapid cycles of mitosis in the syncytium.     

Laser pump and X-ray probe surface photovoltage spectroscopy on Si(111)

Abstract

Laser pump and X-ray probe core-level photoemission experiments probe surface photovoltage transients on p-type Si(111) surfaces. The data are consistent with a picture where the dynamics of mobile surface charge dominate the photovoltage shift, with changes in the surface-states charge density of only secondary importance. A value for the equilibrium band bending is determined, which suggests that a residual oxide layer reduces the density of surface states.     

A Multichannel Signal Processor for the Detection of Epileptogenic Sharp Transients in the EEG

A high-speed multichannel signal processing system is described which is capable of performing automated detection of epileptogenic sharp transients (ST) in the electroencephalogram (EEG). The system is implemented with individually programmable microprocessors on the input channels, followed by a single-board microcomputer which correlates results obtained from each channel, and can process data played back from a tape recorder at a speed eight times the realtime recording speed. A multichannel correlation algorithm is used to enhance the performance of the system in the presence of muscle artifact (EMG). Results are presented showing that the multichannel correlation is capable of reducing, in some cases, both missed detections due to poorly defined ST's and false alarms due to EMG.     

FRACTIONATION OF ASPHALT MATERIALS BY USING SUPERCRITICAL CYCLOHEXANE AND PENTANE

Fractionation of asphalt materials by using supercritical cyclohexane and pentane has been successfully conducted. Each of three asphalts was fractionated into ten fractions. These asphalts and their fractions were then characterized by a variety of analyses including Corbett chromatographic separation, infrared analysis, refractive index- and intrinsic viscosity-size exclusion chromatography (gel permeation chromatography), and elemental analysis by atomic absorption. The fractions were then reblended to produce materials of typical asphalt consistency. These blends were then subjected to oxidative aging in a pressure oxidation vessel and were found, in some cases, to have improved aging characteristics in the sense that they did not harden in response to a given carbonyl formation (oxidation) as much as normal asphalt materials. Hence, the supercritical fractionation technique is considered to have great potential for producing improved asphalt materials.     

Distinctiveness of encoding and memory for learning tasks.

A distinctiveness of encoding hypothesis, as applied to the facilitative effects that higher order objectives appear to have on readers' recall for prose, was evaluated in 3 experiments. Also, the effects of different levels of difficulty of decisions during encoding were examined using an externally referenced difficulty-of-learning task hierarchy. Ss were 253 undergraduates. In a series of identification tasks, decisions about higher order objectives were difficult and resulted in higher levels of recall than did decisions about lower order objectives. Specific controls for processing time, processing ability, and meaningfulness of material did not alter the overall results. It is suggested that distinctiveness of encoding may offer a theoretical basis for the effects of adjunct aids as well as a guide to their construction. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)