Sectoral Heterogeneity, Income Inequality and Productivity Dynamics

An intricate dynamic pattern has been commonly observed in many developed countries during the past decades. This pattern contains a simultaneous rise in the following economic variables: (i) total factor productivity, (ii) educated labor supply, (iii) wage-gap between high- and low-skilled workers, and (iv) income inequality. Typical explanations for the different elements of this pattern assume a skill-biased technical change (SBTC) or capital-skill complementarity. In this study we offer a complementing explanation for these phenomena, which is based on sectoral heterogeneity and endogenous factor mobility, rather than on an SBTC. We show that sectoral heterogeneity can amplify the effects of a technical change, whether skill-biased or general, in a manner that generates the four elements of the above described dynamic pattern. Furthermore, inequality can perform also a Kuznets-curve pattern, as was observed in several countries, in contrast to the inequality dynamics in typical SBTC models.

The Measurement of Health-Related Quality of Life of Girls with Mild to Moderate Idiopathic Scoliosis—Comparison of ISYQOL versus SRS-22 Questionnaire

This study aimed to compare the Italian Spine Youth Quality of Life Questionnaire (ISYQOL-PL) versus the Scoliosis Research Society-22 (SRS-22) questionnaire scores evaluating the validity of the concurrent and known-groups. Eighty-one girls (mean age 13.5 ± 1.8 years) with idiopathic scoliosis (IS) with a mean Cobb angle of 31.0 (±10.0) degrees were examined, all treated with a corrective TLSO brace for an average duration of 2.6 (±1.9) years. The patients’ scores were compared as follows: (1) age: ≤13 years vs. >13 years); (2) scoliosis severity: mild (Cobb angle 10–30°) vs. moderate (Cobb angle >30°); (3) single curve pattern vs. double curve pattern. Lin’s concordance correlation coefficient was used to evaluate the strength of the association between ISYQOL-PL and SRS-22 scores. T-tests were applied to assess if the ISYQOL-PL measure and SRS-22 total score were significantly different in the different groups of patients. The concurrent validity analysis showed a moderate correlation (Lin pccc = 0.47). The ISYQOL-PL showed a significantly better quality of life in mild than moderate scoliosis. The severity of scoliosis but not the age or the curve pattern demonstrated a direct statistically significant effect on patients’ quality of life only when evaluated using the ISYQOL-PL.

A straightforward molecular strategy to retrospectively investigate the spread of SARS-CoV-2 VOC202012/01 B.1.1.7 variant

The spread of new SARS-CoV-2 variants represents a serious threat worldwide, thus rapid and cost-effective methods are required for their identification. Since November 2020, the TaqPath COVID-19 assay (Thermo Fisher Scientific) has been used to identify viral strains of the new lineage B.1.1.7, since it fails to detect the S-gene with the ∆69/70 deletion. Here, we proposed S-gene mutations screening with the Allplex SARS-CoV-2 assay (Seegene), another widely used RT-PCR test that targets Sarbecovirus E, SARS-CoV-2 N, and RdRp/S genes. Accordingly, we evaluated the S gene amplification curve pattern compared to those of the other genes. Exploiting an Allplex assay-generated dataset, we screened 663 RT-PCR digital records, including all SARS-CoV-2 respiratory samples tested in our laboratory with the Allplex assay between January 1st and February 25th, 2021. This approach enabled us to detect 64 samples with peculiar non-sigmoidal amplification curves. Sequencing a selected group of 4 RNA viral genomes demonstrated that those curves were associated with B.1.1.7 variant strains. Our results strongly suggest that B.1.1.7 variant spread has begun in this area at least since January and imply the potential of these analytical methods to track and characterize the spread of B.1.1.7 strains in those areas where Allplex SARS-CoV-2 datasets have been previously recorded.

Does the Level of Pedicle Subtraction Osteotomy Affect the Surgical Outcomes in Ankylosing Spondylitis-Related Thoracolumbar Kyphosis With the Same Curve Pattern?

Study Design: A retrospective study. Objective: To investigate the effect of pedicle subtraction osteotomy (PSO) level on the surgical outcomes in ankylosing spondylitis-related thoracolumbar kyphosis with the same curve pattern. Methods: ankylosing spondylitis (AS) patients with thoracolumbar kyphosis, who underwent 1-level lumbar PSO between March 2006 and June 2017, were retrospectively reviewed. Criteria for curve-matched thoracolumbar kyphosis were: (1) have same level of preoperative apex (pre-apex); (2) have similar global kyphosis (GK, the angle between the superior/inferior endplate of the maximally tilted upper and lower end vertebra) (the difference of GK less than 15˚). The radiographic parameters measured were sagittal vertical axis (SVA, the horizontal distance between the C7 plumb line and the posterosuperior corner of the S1), GK, thoracic kyphosis (TK, the angle between the T5 superior endplate and the T12 inferior endplate), lumbar lordosis (LL, the angle between the L1 and S1 superior endplate), sacral slope (SS, the angle between the sacral endplate and the horizontal line), pelvic tilt (PT, the angle between the vertical and the line joining the midpoint of the sacral plate and hip axis), and pelvic incidence (PI, the angle between the line vertical to the superior margin of S1 and the line connecting the sacral plate midpoint with the hip joint axis). All of these parameters and health-related quality of life (HRQoL, evaluated by preoperative and the last follow-up questionnaires including ODI and VAS) scores were collected before surgery and at the last follow-up. According to their osteotomy level, patients were devided into 2 sub-groups (L1 group and L2 group), and differences of these mentioned parameters between 2 groups were compared. Results: 26 curve-matched patients were recruited with a mean follow-up of 37.2 months. All patients improved significantly after surgery in HRQoL scores (VAS 1.6 vs 5.4, P < 0.001; ODI 11.9 vs 26.4, P < 0.001). Except for TK and PI, those radiographic parameters were also observed to be significantly changed after surgery. Compared to L2 group, PSO at L1 may have larger correction of TK (ΔTK -6.8 vs -0.3°, P = 0.164), PI (ΔPI -7.4 vs -0.7°, P = 0.364) and smaller correction of SVA (ΔSVA -105.3 vs -128.5 mm, P = 0.096), LL (ΔLL -31.1 vs -43.0°, P = 0.307) and SS (ΔSS 6.9 vs 12.2°, P = 0.279) but had no statistical significance. Conclusion: The results of this investigation showed that in AS-related thoracolumbar kyphosis patients with the same curve pattern, the different levels of osteotomy had little effect on the improvement of surgical outcomes. However, osteotomy at L2 is more likely to obtain a larger correction of SVA compared to osteotomy at L1.

Does curve pattern impact on the effects of physiotherapeutic scoliosis specific exercises on Cobb angles of participants with adolescent idiopathic scoliosis: A prospective clinical trial with two years follow-up

Background Current clinical evidence suggests that a well-planned physiotherapeutic scoliosis specific exercise (PSSE) program is effective for scoliosis regression. Objectives We investigated the effect of curve patterns on Cobb angles with PSSE. Methods This was a non-randomized prospective clinical trial that recruited participants with adolescent idiopathic scoliosis between January and June 2017. Participants were grouped by curve pattern into major thoracic and major lumbar groups. An outpatient-based PSSE program was conducted with the following schedule of intensive exercise: ≥ 1 session of supervised PSSE per month and > 30min of home exercise 5 days/week in the first 6 months, after which exercise frequency was reduced to 1 session of supervised PSSE every three months and > 30min of home exercise 5 days/week until 2 years after study initiation. Radiographic Cobb angle progressions were identified at the 1, 1.5 and 2-year follow-ups. A mixed model analysis of variance (ANOVA) was performed to examine the differences in Cobb angles between groups at four testing time points. The two-tailed significance level was set to 0.05. Results In total, 40 participants were recruited, including 22 with major thoracic curves (5 males and 17 females; mean age 13.5±1.8 years; Cobb angle 18–45 degrees) and 18 with major lumbar curves (7 males and 11 females; mean age 12.7±1.7 years; Cobb angle 15–48 degrees). Curve regressions, namely the reduction of Cobb angles between 7 to 10 degrees were noted in 9.1% of participants in the major thoracic group; reductions of 6 to 13 degrees were noted in 33.3% of participants in the major lumbar group at the 2-year follow-up. Repeated measurements revealed a significant time effect (F2.2,79.8 = 4.1, p = 0.02), but no group (F2.2,79.8 = 2.3, p = 0.1) or time × group (F1,37 = 0.97, p = 0.3) effects in reducing Cobb angles after 2 years of PSSE. A logistic regression analysis revealed that no correlation was observed between curve pattern and curve regression or stabilization (OR: 0.2, 95% CI: 0.31–1.1, p = 0.068) at the 2-year follow-up. Conclusion This was the first study to investigate the long-term effects of PSSE in reducing Cobb angles on the basis of major curve location. No significant differences in correction were observed between major thoracic and major lumbar curves. A regression effect and no curve deterioration were noted in both groups at the 2-year follow-up. Trial registration ChiCTR1900028073.

Organizational Learning Processes and Outcomes: Major Findings and Future Research Directions

We trace the evolution of research on organizational learning. As organizations acquire experience, their performance typically improves at a decreasing rate. Although this learning-curve pattern is found in many industries, organizations vary in the rate at which they learn. In order to understand this variation, we separate organizational learning into four processes: search, knowledge creation, knowledge retention, and knowledge transfer. Within each process, we present research on how dimensions of experience and of the organizational context affect learning processes and outcomes. Our goals are to describe major findings and to identify opportunities for future research. The article concludes with a discussion of research directions that are likely to be productive in the future. These directions include investigating how new technological and organizational developments are likely to affect organizational learning. This paper was accepted by David Simchi-Levi, finance.

Diagnostic Accuracy of Differentiation between Primary Central Nervous System Lymphoma and High-Grade Glioma Using Dynamic Susceptibility Contrast Perfusion Curve Analysis

Objective: To determine diagnostic accuracy of visualized dynamic susceptibility contrast (DSC) perfusion curve pattern in differentiation between primary central nervous system lymphoma (PCNSL) and high-grade glioma (HGG). Materials and Methods: Forty-one patients (nineteen cases of PCNSL and twenty-two cases of HGG) acquired between January 2010 and November 2017 were included in the present study. The DSC perfusion curve patterns were retrospectively reviewed by two neuroradiologists, divided into two patterns as 1) return of time-intensity curve above the baseline after initial drop, and 2) return of time-intensity curve below or equal to baseline. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy were analyzed. Results: Return of time-intensity curve above the baseline on DSC perfusion was found in 15 of 19 (78.9%) PCNSL cases, and only two of 22 (9.1%) HGG cases, p-value<0.001; whereas return of time-intensity curve below or equal to baseline was found in only four of 19 (21.1%) PCNSL cases and 20 of 22 (90.9%) HGG cases, p-value<0.001. Return of time-intensity signal curve above the baseline pattern had sensitivity of 78.9%, specificity of 90.9%, PPV of 88.2%, NPV of 88.3%, and accuracy of 85.4% for diagnosis of PCNSL, respectively. Conclusion: Visualized DSC curve pattern has a role in differentiation between PCNSL and HGG. Presence of return of time-signal intensity curve above the baseline could suggest the diagnosis of PCNSL. Keywords: PCNSL, HGG, DSC perfusion, Curve analysis, Return curve above baseline