SU(1,1) symmetry of multimode squeezed states

We show that a class of multimode optical transformations that employ linear optics plus two-mode squeezing can be expressed as SU(1,1) operators. These operations are relevant to state-of-the-art continuous variable quantum information experiments including quantum state sharing, quantum teleportation, and multipartite entangled states. Using this SU(1,1) description of these transformations, we obtain a new basis for such transformations that lies in a useful representation of this group and lies outside the often-used restriction to Gaussian states. We analyze this basis, show its application to a class of transformations, and discuss its extension to more general quantum optical networks

Validation of the movement system impairment-based classification in patients with knee pain

Background: Categorizing patients with knee pain problems based on pathoanatomical sources has not proved to be the most effective method for directing physical therapy interventions. Movement system impairment (MSI) classification system may be an alternative in the assessment, diagnosis, and management of patients with knee pain. No previous study has been conducted to validate the proposed system in these patients. Objective: To assess construct validity of the MSI classification system in patients with knee pain. Design: A cross-sectional methodological study. Setting: Rasul Akram Hospital. Participants: One hundred eighty subjects with knee pain aged 18-65 years. Methods: The MSI classification recognizes seven categories of knee pain problems based on the findings from the symptoms and signs assessment. Three physical therapists examined subjects with knee pain. A principal component analysis (PCA) was used to derive proposed categories. Eigenvalues and a scree plot were also used to determine the factor retention. Results: Four factors related to three proposed categories were extracted from the PCA. Two factors were related to tibiofemoral rotation (TFR) category. The other two factors were related to proposed categories patellar lateral glide (PLG) and tibiofemoral hypomobility (TFHypo). Conclusion: The results provided evidence for the construct validity of three (TFR, PLG, and TFHypo) of the seven categories proposed by MSI classification. In addition TFR was subcategorized into two groups which were named as tibial lateral rotation (TLR) and femoral adduction/medial rotation (FAdd/MR) in the present study. © 2016 Elsevier Ltd

Intratester and intertester reliability of the movement system impairment-based classification for patients with knee pain

Background The methods to standardize the test items used for classification of patients with knee pain based on the movement system impairment (MSI) approach have been established. To our knowledge, no study has concentrated on establishing reliability for proposed classification for knee pain problems. Objective The aim of the study was to assess intra- and intertester reliability of the knee MSI classification in patients with knee pain. Design A cross-sectional methodological study. Setting Rasul Akram Hospital. Participants Ninety-six subjects with knee pain aged 18�65 years. Methods In order to examine intertester reliability, all three testers assessed the symptoms, signs and the MSI diagnosis of subjects with knee pain simultaneously. In order to assess intratester reliability, the procedure was exactly repeated after a one-week intersession period. Kappa values and percentages of agreement were calculated to analyze the reliability level. Results The kappa values for intra- and intertester reliability of the symptom items ranged from 0.83 to 1.00 and 0.00 to 0.83, respectively. For the sign items, the kappa values ranged from 0.18 to 1.00 and 0.00 to 0.82, respectively. Finally, the kappa values of intra- and intertester reliability for patients' classification judgments ranged from 0.66 to 0.71, and 0.48 to 0.58, respectively. Conclusion The results of the present study indicate that intertester reliability for the symptoms, signs and classification judgments of patients with knee pain based on the MSI approach seemed generally acceptable. However, for intratester reliability, lower levels of the system were observed, probably due to different pain levels or pain behavior between test and retest sessions. © 2016 Elsevier Lt