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Introduction: Low back pain is a common problem affecting millions worldwide. Even after surgical treatment some patients do not improve; others suffer from persistent radiculopathy. We define Complex Chronic Low Back Pain (CCLBP) as any low back pain that has lasted for at least three months and has at least two triggering pain mechanisms. Objective: To describe our experience with plateletrich plasma (PRP) therapy in managing CCLBP with a neuropathic component Methods: Quantitative, retrospective analysis from 57 medical records of patients treated with PRP for CCLBP. We used IBMSPSS 21 to obtain descriptive statistics, Chi-square, Student T and Odds-Ratio. Results: The mean age of our sample was 59.8 (±14.4) years, with 6.51 (±8.7) years of pain and a follow-up of 9 (±12.2) months. 33.3% had lumbar surgery, 29.8% had lumbar trauma, 31.6% used a walking aid, 56.7% had MODIC changes on MRI, and 42% of them received intraosseous-PRP technic. 84.2% reported severe pain (VAS 8-10). The results showed that 96.5% of patients experienced some improvement after PRP treatment. Additionally, 10.5% experienced pain suppression. No significant differences in age, lumbar trauma, lumbar surgery, diseases, or the use of walking aids between patients who benefited from PRP treatment and those who did not. VAS after treatment shows significance (p<0.01) with 5.36±2.6 points. Subjects with less than five years of radicular pain had an improvement greater than 3 points on VAS (OR 7.38, IC95% 1.72-31.7). Conclusion: Autologous platelet-rich plasma injections for chronic low back pain with a neuropathic component are an effective alternative to address CCLBP's current challenge. New studies with greater statistical power are necessary to make a statement of efficacy, but with the data obtained, it seems a promising option. [ABSTRACT FROM AUTHOR]

Since the breakthrough of twistronics a plethora of topological phenomena in correlated systems has appeared. These devices can be typically analyzed in terms of lattice models using Green's function techniques. In this work we introduce a general method to obtain the boundary Green's function of such models taking advantage of the numerical Faddeev-LeVerrier algorithm to circumvent some analytical constraints of previous works. We illustrate our formalism analyzing the edge features of a Chern insulator, the Kitaev square lattice model for a topological superconductor and the Checkerboard lattice hosting topological flat bands. The efficiency and accuracy of the method is demonstrated by comparison to standard recursive Green's function calculations and direct diagonalizations.

Forecasts about the effects of new technologies on labor demand are generally pessimistic. However, little is known about the current level of technology adoption and its effect on labor demand, particularly in developing countries. This paper exploits a national representative employer survey and administrative data from Peru to offer empirical evidence in this regard. Our results show that the adoption of new technologies by firms is still incipient in the country. However, when adopted, they slightly reduce the demand for workers in the medium term, particularly those in high-skilled and non-routine occupations, with a temporary job contract, and during the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

Teak (Tectona grandis L.f.) is an important species in the worldwide quality tropical hardwood sector, which has gained significance in Central America since the first large plantations were established in the 1980s. The present work is a descriptive study that aims to: (1) analyse and characterise the general soil patterns which may be influencing teak plantations in Central America; (2) assess differences between countries and sub-regions; (3) create a global framework to help contextualise the soil fertility analyses conducted at sub-regional or farm level, and (4) determine the main problems associated with soil fertility in the region. Soil fertility was measured at 684 sites in Costa Rica, Guatemala and Panama. Although teak is considered to be a species with high soil nutrient requirements, and high fertility is usually assumed in teak plantations, the results show that this species has been planted in a wide variety of soils, including many with serious fertility problems (e.g. Ultisols and perhaps Oxisols) or with added difficulties due to their physical properties (e.g. Vertisols). The present analysis reveals a general K deficiency in the Central American teak plantations, where P deficiency and acidity toxicity are also relatively common problems. These soil fertility problems probably stem from poor site selection by forest managers in the 80s and 90s. Hence, although soil fertility is carefully evaluated when most teak plantations are established today, managers have to deal with soil fertility deficiencies in many sites where teak was established some years ago. Additional keywords: forest nutrition, forest plantations, forest soils, planted forests, site selection, tropical soils. Received 11 September 2014, accepted 29 January 2015, published online 30 June 2015, Introduction Teak (Tectona grandis L.f.) is an important species in the worldwide quality tropical hardwood sector, with a total planted area of 4.3 x [10.sup.6] ha (Pandey and Brown 2000; [...]

This paper studies the role of cognitive skills, socioemotional skills, aspirations and expectations on the likelihood of being NEET (not in education, employment or training) using a novel sample of 15 to 24 year old residents of seven Latin American and Caribbean countries. After controlling for sociodemographic household conditions, we find that numeracy and literacy skills, core self‐evaluation, extraversion and educational aspirations are robust correlates of being NEET. We also find cross country heterogeneity. That is, in some countries, passion and perseverance for long‐term goals, neuroticism and labour market information biases are additional factors associated with being NEET. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]