PROGRAMACIÓN DINÁMICA Y DUALIDAD, APLICADA AL USO ÓPTIMO DE RECURSOS EN UN SISTEMA DE GENERACIÓN SIMILAR AL DE PANAMÁ

Panama’s generation system has an important renewable energy component, similar to what happens in other Central American countries. There is a significant renewable energy storage capacity in reservoirs that allow planning strategies to mitigate costs between seasons. The decisions taken today affect situations in the future in this kind of problem. Scheduling of the hydro reservoirs use is necessary because it can save costs in the future. One way to implement this scheduling is by pricing the hydro resource over time. The dual approach to this problem offers the possibility of addressing it from the shadow prices point of view. To solve these problems, they must be broken down into sub-problems that are interrelated. The strategy of solving complex optimization problems by broken in sequential sub-problems is dynamic programming. This paper focuses on the problem of optimizing the use of resources applicable to the Panamanian system, which apply Dynamic Programming and Dual approach of Linear Programming.Al igual que en la región centroamericana, el sistema de generación panameño cuenta con un importante componente de energía renovable dentro de los cuales existe una significativa capacidad de almacenamiento mediante embalses, que permite planificar estrategias para mitigar costos entre estaciones. En la planificación del uso de los recursos de generación de estos sistemas, se toman decisiones que afectan la situación en el futuro.  Una manera de organizar esta política de decisiones es mediante la asignación de precios a lo largo del tiempo para los recursos que pueden ser administrados.  El planteamiento dual de este problema ofreció la posibilidad de abordar el problema desde el punto de vista de los precios sombra. Fue necesario descomponer el problema en sub-problemas que se entrelazan sucesivamente. Esta estrategia de resolver un problema de optimización complejo mediante la descomposición del problema en sub-problemas secuenciales corresponde a la Programación Dinámica. Se abordó el problema de optimización del uso de recursos de generación eléctrica aplicable al sistema panameño, con el uso de la Programación Dinámica y de la Dualidad de Programación Lineal

Programación dinámica y dualidad, aplicada al uso óptimo de recursos en un sistema de generación similar al de Panamá

Al igual que en la región centroamericana, el sistema de generación panameño cuenta con un importante componente de energía renovable dentro de los cuales existe una significativa capacidad de almacenamiento mediante embalses, que permite planificar estrategias para mitigar costos entre estaciones. En la planificación del uso de los recursos de generación de estos sistemas, se toman decisiones que afectan la situación en el futuro. Una manera de organizar esta política de decisiones es mediante la asignación de precios a lo largo del tiempo para los recursos que pueden ser administrados. El planteamiento dual de este problema ofreció la posibilidad de abordar el problema desde el punto de vista de los precios sombra. Fue necesario descomponer el problema en sub-problemas que se entrelazan sucesivamente. Esta estrategia de resolver un problema de optimización complejo mediante la descomposición del problema en sub-problemas secuenciales corresponde a la Programación Dinámica. Se abordó el problema de optimización del uso de recursos de generación eléctrica aplicable al sistema panameño, con el uso de la Programación Dinámica y de la Dualidad de Programación Lineal

La geometría y su relación con el pensamiento espacial en la educación superior

Este estudio examina la relación entre el aprendizaje de la geometría y el desarrollo de habilidades del pensamiento espacial en estudiantes de primer año 2023, de la Facultad de Ciencias Naturales, Exactas y Tecnología de la Universidad de Panamá. Se utilizó un enfoque cuantitativo de tipo correlacional, con un diseño preexperimental con pruebas pretest y postest en un solo grupo de estudiantes. La muestra final estuvo compuesta por 20 participantes, seleccionados mediante un muestreo no probabilístico por conveniencia, aunque inicialmente se había previsto contar con 29 participantes. Para la obtención de información, se utilizaron dos instrumentos: un cuestionario de 20 ítems que midió el aprendizaje de la geometría y la prueba psicométrica estandarizada Batería General de Pruebas de Aptitud (GATB) para evaluar el pensamiento espacial. El análisis estadístico realizado mediante la Prueba del Coeficiente de Correlación de Pearson mostró una relación significativa entre las dos variables. La correlación, que inicialmente era moderada, tendió a fuerte, lo que sugiere que un mayor desarrollo del pensamiento espacial está asociado con un mejor desempeño en geometría, reduciendo la posibilidad de un bajo rendimiento en esta materia

A PSA SNP associates with cellular function and clinical outcome in men with prostate cancer

Genetic variation at the 19q13.3 KLK locus is linked with prostate cancer susceptibility in men. The non-synonymous KLK3 single nucleotide polymorphism (SNP), rs17632542 (c.536 T > C; Ile163Thr-substitution in PSA) is associated with reduced prostate cancer risk, however, the functional relevance is unknown. Here, we identify that the SNP variant-induced change in PSA biochemical activity mediates prostate cancer pathogenesis. The ‘Thr’ PSA variant leads to small subcutaneous tumours, supporting reduced prostate cancer risk. However, ‘Thr’ PSA also displays higher metastatic potential with pronounced osteolytic activity in an experimental metastasis in-vivo model. Biochemical characterisation of this PSA variant demonstrates markedly reduced proteolytic activity that correlates with differences in in-vivo tumour burden. The SNP is associated with increased risk for aggressive disease and prostate cancer-specific mortality in three independent cohorts, highlighting its critical function in mediating metastasis. Carriers of this SNP allele have reduced serum total PSA and a higher free/total PSA ratio that could contribute to late biopsy decisions and delay in diagnosis. Our results provide a molecular explanation for the prominent 19q13.3 KLK locus, rs17632542 SNP, association with a spectrum of prostate cancer clinical outcomes

A PSA SNP associates with cellular function and clinical outcome in men with prostate cancer

Funder: Department of Health | National Health and Medical Research Council (NHMRC); doi: https://doi.org/10.13039/501100000925Funder: Prostate Cancer Foundation of Australia (PCFA); doi: https://doi.org/10.13039/501100000927AbstractGenetic variation at the 19q13.3 KLK locus is linked with prostate cancer susceptibility in men. The non-synonymous KLK3 single nucleotide polymorphism (SNP), rs17632542 (c.536 T &gt; C; Ile163Thr-substitution in PSA) is associated with reduced prostate cancer risk, however, the functional relevance is unknown. Here, we identify that the SNP variant-induced change in PSA biochemical activity mediates prostate cancer pathogenesis. The ‘Thr’ PSA variant leads to small subcutaneous tumours, supporting reduced prostate cancer risk. However, ‘Thr’ PSA also displays higher metastatic potential with pronounced osteolytic activity in an experimental metastasis in-vivo model. Biochemical characterisation of this PSA variant demonstrates markedly reduced proteolytic activity that correlates with differences in in-vivo tumour burden. The SNP is associated with increased risk for aggressive disease and prostate cancer-specific mortality in three independent cohorts, highlighting its critical function in mediating metastasis. Carriers of this SNP allele have reduced serum total PSA and a higher free/total PSA ratio that could contribute to late biopsy decisions and delay in diagnosis. Our results provide a molecular explanation for the prominent 19q13.3 KLK locus, rs17632542 SNP, association with a spectrum of prostate cancer clinical outcomes.</jats:p

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research