Predicción probabilística de corto plazo en generación eólica

A través de este proyecto se describe el uso del clasificador del K n-ésimo vecino más cercano KNN y un estimador del kernel con el fin de predecir la potencia eólica del viento. El modelo es capaz de predecir valores de la potencie eólica generada a la salida de la granja con una antelación de hasta 48h. Los datos usados para el estudio de caso tienen una resolución por cada hora. Estos datos fueron obtenidos de 10 granjas ubicadas en Australia, a dos distintas alturas: 10m y 100m. El modelo desarrollado es un modelo de un único paso. En la primera Fase, el KNN es usado para filtrar los datos. Una vez los datos han sido filtrados y normalizados, el modelo predice escenarios de generación a través del estimador del kernel. Finalmente, algunos indicadores de desempeño son usados para medir los resultados obtenidos respecto del valor real, tales como: EM, EMAN, EPMA y DEE.Abstract: This project describes the use of KNN classifier with Kernel Density Estimation (KDE) models to forecasting the wind power. This approach is used to predict hourly values of wind power for horizons of up to 48h. The data used is hourly observation from 10 wind farms at two different heights, 10m and 100m, in Australia. This approached is a one-stage method where first a KNN classifier is applied to the raw data to clean it. Once the dataset has been cleaned and normalized, the forecast of the normalized wind power is calculated using KDE models. MAE, MAPE and SDE performance indices are used to find the performance of this model.Maestrí

Trapping light in air with membrane metasurfaces for vibrational strong coupling

Optical metasurfaces can manipulate electromagnetic waves in unprecedented ways at ultra-thin engineered interfaces. Specifically, in the mid-infrared (mid-IR) region, metasurfaces have enabled numerous biochemical sensing, spectroscopy, and vibrational strong coupling (VSC) applications via enhanced light-matter interactions in resonant cavities. However, mid-IR metasurfaces are usually fabricated on solid substrates, which degrade resonance quality factors (Q) and hinder efficient sample access to the near-field electromagnetic hotspots. Besides, typical IR-transparent substrate materials, such as CaF2, NaCl, KBr, and ZnSe, are usually either water-soluble, expensive, or not compatible with low-cost mass manufacturing processes. To address these substrate-related technological limitations, we present novel substrate-less mid-IR metasurfaces with strong light-trapping capabilities in accessible air voids through the patterning of free-standing Si-membranes. We employed the Brillouin zone folding technique to excite high-Q quasi-bound states in the continuum (q-BIC) resonances. Leveraging the strong field localizations in accessible air cavities (|E/E0|>200), we demonstrated VSC between molecules and the q-BIC modes. Our new approach of fabricating mid-IR metasurfaces into semiconductor membranes enables low-cost manufacturing of MIR photonic devices and provides exciting opportunities for quantum-coherent light-matter interactions, biochemical sensing, and polaritonic chemistry

Cuantificación del ahorro de energía eléctrica en clientes residenciales mediante acciones de gestión de demanda

Colombia enfrentó entre 2015 y 2016 uno de los fenómenos de El Niño más severos de su historia quedando ad-portas de un racionamiento de energía. La gestión de demanda puede ayudar, entre otros aspectos, a reducir el consumo de energía en cualquier escenario de disponibilidad de recursos energéticos, no sólo en emergencia. El artículo presenta la cuantificación de los posibles ahorros en clientes residenciales en Bogotá D.C., determinados a partir del modelado de diferentes estrategias de gestión de demanda. Los resultados muestran que pueden lograrse reducciones en el consumo entre 6 y 26% mediante sustitución de dispositivos, 7 y 19% mediante cambio de hábitos de consumo, y entre 17% y 45% como ahorro total posible. Los resultados también revelan que los clientes con menores consumos de energía pueden alcanzar ahorros de hasta el 45%, mientras que los clientes con consumos mayores de 150 kWh/mes no logran ahorros superiores al 20%.Colombia faced from 2015 to 2016 one of most severe El Niño whether phenomenal in its history, being close to energy rationing. Demand management can help to reduce energy consumption under any scenario of energy availability, not only under emergencies. This article presents the quantification of potential savings in residential customers in Bogotá D.C., determined from the modeling of different demand management strategies. The results show energy reduction between 6 and 26% resorting to device substitution, 7 and 19% through energy consumption patterns adjustments, and between 17% and 45% as possible total energy savings. The results reveal as well that customers with low energy consumption can reach upto 45% savings, in contrast to customers with consumption energy greater than 150 kWh/month cannot reach energy saving above 20%

Cuantificación del ahorro de energía eléctrica en clientes residenciales mediante acciones de gestión de demanda

Colombia enfrentó entre 2015 y 2016 uno de los fenómenos de El Niño más severos de su historia quedando ad-portas de un racionamiento de energía. La gestión de demanda puede ayudar, entre otros aspectos, a reducir el consumo de energía en cualquier escenario de disponibilidad de recursos energéticos, no sólo en emergencia. El artículo presenta la cuantificación de los posibles ahorros en clientes residenciales en Bogotá D.C., determinados a partir del modelado de diferentes estrategias de gestión de demanda. Los resultados muestran que pueden lograrse reducciones en el consumo entre 6 y 26% mediante sustitución de dispositivos, 7 y 19% mediante cambio de hábitos de consumo, y entre 17% y 45% como ahorro total posible. Los resultados también revelan que los clientes con menores consumos de energía pueden alcanzar ahorros de hasta el 45%, mientras que los clientes con consumos mayores de 150 kWh/mes no logran ahorros superiores al 20%.Colombia faced from 2015 to 2016 one of most severe El Niño whether phenomenal in its history, being close to energy rationing. Demand management can help to reduce energy consumption under any scenario of energy availability, not only under emergencies. This article presents the quantification of potential savings in residential customers in Bogotá D.C., determined from the modeling of different demand management strategies. The results show energy reduction between 6 and 26% resorting to device substitution, 7 and 19% through energy consumption patterns adjustments, and between 17% and 45% as possible total energy savings. The results reveal as well that customers with low energy consumption can reach upto 45% savings, in contrast to customers with consumption energy greater than 150 kWh/month cannot reach energy saving above 20%

Power distribution transformers using natural ester fluids as dielectric and coolant

Researches related with the use of Natural Ester Fluids as refrigerant of power transformers has been developed in other countries with successful re-sults. In Colombia there is no a procedure to control the use of these esters in electrical apparatus, so the cur-rent implementations are regulated by NTC 1465 stan-dards for mineral esters. This new proposal involves the composition and the most relevant properties (the ignition resistance, impact on the lifetime of the in-sulating papers and the impact on the environment), which makes the application of natural esters fluids advantageous not only to preserve the environment but also to get a better performance of power transformers.Las investigaciones en desarrollo respecto al uso de aceites de origen vegetal como refrigerantes en transformadores de distribución han tenido resultados destacados en otros países. En Colombia no existe un procedimiento para monitorear la aplicación de estos aceites en equipos eléctricos, por lo tanto, la actual implementación se regula por la norma técnica NTC 1465 para aceites de origen mineral. Esta propuesta de nueva tecnología contempla la composición y las propiedades más relevantes (resistencia a la ignición, impacto en el tiempo de vida del papel e impacto en el medio ambiente), lo cual provee de mayor número de ventajas al aceite vegetal y un mejor desempeño en eficiencia

Association between Inflammation and Cardiac Geometry in Chronic Kidney Disease: Findings from the CRIC Study.

Background Left ventricular hypertrophy (LVH) and myocardial contractile dysfunction are independent predictors of mortality in patients with chronic kidney disease (CKD). The association between inflammatory biomarkers and cardiac geometry has not yet been studied in a large cohort of CKD patients with a wide range of kidney function. Methods Plasma levels of interleukin (IL)-1β, IL-1 receptor antagonist (IL-1RA), IL-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, high-sensitivity C-Reactive protein (hs-CRP), fibrinogen and serum albumin were measured in 3,939 Chronic Renal Insufficiency Cohort study participants. Echocardiography was performed according to the recommendations of the American Society of Echocardiography and interpreted at a centralized core laboratory. Results LVH, systolic dysfunction and diastolic dysfunction were present in 52.3%, 11.8% and 76.3% of the study subjects, respectively. In logistic regression analysis adjusted for age, sex, race/ethnicity, diabetic status, current smoking status, systolic blood pressure, urinary albumin- creatinine ratio and estimated glomerular filtration rate, hs-CRP (OR 1.26 [95% CI 1.16, 1.37], p Conclusion In patients with CKD, elevated plasma levels of hs-CRP and IL-6 are associated with LVH and systolic dysfunction

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362