Metodología dinámica de análisis de supervivencia aplicada a credit scoring

136 p.Esta investigación busca confeccionar una metodología que permita detectar y modelar cambios sufridos a lo largo del tiempo en los patrones que definen una clasificación en modelos de Análisis de Supervivencia. La Metodología Dinámica de Análisis de Supervivencia (MDAS) propuesta utiliza tres diferentes algoritmos de detección de cambios en los datos, con los cuales se entrenan modelos de Riesgos Proporcionales de Cox de manera independiente para luego seleccionar como modelo final aquel que minimice el error sobre un conjunto de prueba. La MDAS fue aplicada a un caso real de Credit Scoring con tres instancias de tiempo, y los resultados obtenidos fueron contrastados con los alcanzados por la metodología estática correspondiente con el fin de ilustrar la verdadera utilidad del método desarrollado. La metodología propuesta alcanzó una efectividad en promedio superior al modelo estático, lo cual fue estadísticamente comprobado. Por lo tanto, se logró desarrollar una metodología capaz de utilizar los datos más relevantes para el modelamiento del concepto objetivo de estudio. Adicionalmente, el Modelo de Riesgos Proporcionales de Cox ofrece una favorable interpretación de resultados que permitió analizar variables y aspectos relevantes en el riesgo de no pago. Palabras claves: Análisis de Supervivencia, Modelo de Riesgos Proporcionales de Cox, Metodología Dinámica, Credit Scoring. Abstract This research aims to make a methodology able to detect and model changes occurred along the time to the patterns which define a classification in Survival Analysis models. The called Dynamic Survival Analysis Methodology (MDAS) uses three different data change detection algorithms, which train Cox’s proportional hazards models independently and then selects as final model that one minimizes the global risk on a test set. The MDAS was applied over a real data of Credit Scoring with three time instances, and the outcomes achieved were contrasted versus the static methodology one, in order to show the real usefulness of the developed method. The proposed methodology achieved a higher average effectiveness than the static model, which was statistically proven. Therefore, it was possible to develop a methodology able to use the most relevant data to model the target. Moreover, the Cox’s proportional hazards model gives a useful interpretation of outcomes what allowed analyze characteristic variables and relevant issues in the default risk. Key words: Survival Analysis, Cox’s proportional hazards model, Dynamic Methodology, Credit Scoring

A Pilot Study on the Feasibility of Developing and Implementing a Mobile App for the Acquisition of Clinical Knowledge and Competencies by Medical Students Transitioning from Preclinical to Clinical Years

Due to the COVID-19 pandemic and the consequent restrictions, universities have had to adapt their curricula substantially to new schemes in which remote learning is of the essence. In this study, we assess the feasibility of developing a mobile app supplementary to the distant teaching paradigm for the “Cardiology” module of the “General Pathology” subject in undergraduate Medical Education, and we evaluate its impact and acceptability. A cohort of volunteer second-year medical students (n = 44) had access to the app, and their opinions on its utility (1–10) were collected. Additionally, the students were invited to refer their expected satisfaction (1–10) with a blended learning methodology overlapping this new tool with the traditional resources. The average expected satisfaction had been compared to the average satisfaction obtained by just the traditional methodology in other modules from the same subject. Through a qualitative approach, we defined the strengths and weaknesses of the tool. Seventy-seven percent of the participants rated at 8/10 or more the potential learning value of the application and, if used as a supplement to traditional teaching, it would also statistically improve the satisfaction of students (6.52 vs. 8.70, p < 0.001). Similarly, the qualitative data corroborated the benefits of such innovation. Multidisciplinary collaborations are encouraged to develop teaching innovations, although further research should aim to better define the effectiveness of learning with these resources

Adaptación de leguminosas arbóreas en un sistema silvopastoril para ovinos en clima templado

The objective was to evaluate the survival, production and nutritional value of forage, tree legumes, as well as, grasses and weeds in a silvopastoral system. A mixed protein bank was established made up of trees of legume species: pata de vaca (Bauhinia forficata), albizia (Albizia lebbeck), leucaena (Leucaena leucocephala) and palo dulce (Eysenhardtia polystachya). Three real planting frames were used, with a distance of 70x70, 90x90, and 110x110 cm, between trees. It was counted visually and manually, identifying the species and its condition binomially either alive (1) or dead (0). A three-way classification model with unequal number of repetitions was used by using the procedure for Generalized Linear Models of the statistical analysis system, under a fixed effects model. The nutritional value of tree legumes remained in the range of 11 to 18% for protein. Differences (p ≤ 0.05) were observed between treatments and height orientation. There was an effect (p ≤ 0.05) on the treatment, orientation, period and the four species on foliage production. Differences (p ≤ 0.05) in the survival of the species were observed, highlighting the albizia (Albizia lebbeck). The period influenced (p ≤ 0.05) the survival of the trees. It is concluded that the survival rate for forage tree legume species determines their ability to establish silvopastoral systems in temperate subhumid climates in mixed protein bank arrangements. Keywords: mixed protein bank, density, survival, forage species.El objetivo fue evaluar la supervivencia, la producción y el valor nutricional del forraje, de leguminosas arbóreas asi como de las gramíneas y arvenses en un sistema silvopastoril. Se estableció un banco de proteína mixto conformado por árboles de especies leguminosas: pata de vaca (Bauhinia forficata), albizia (Albizia lebbeck), leucaena (Leucaena leucocephala) y palo dulce (Eysenhardtia polystachya). Se emplearon tres marcos reales de plantación, con una distancia de 70x70, 90x90. y 110x110 cm, entre árboles. Se contabilizo de manera visual y manual, identificando la especie y su condición vivo de manera binomial (1) o muerto (0). Se utilizó un modelo en tres vías de clasificación con desigual número de repeticiones usando el procedimiento para Modelos lineales Generalizados del sistema de análisis estadístico, bajo un modelo de efectos fijos. El valor nutricional de las leguminosas arbóreas se mantuvo en un rango del 11 al 18 % de proteína. Se observaron diferencias (p ≤ 0,05) entre tratamientos y la orientación sobre la altura.&nbsp; Hubo efecto (p ≤ 0,05) sobre el tratamiento, orientación, periodo y las cuatro especies sobre la producción de follaje. Se observaron diferencias (p ≤ 0,05) de supervivencia de las especies destacando la albizia (Albizia lebbeck). El periodo influyo (p ≤ 0,05) en la supervivencia de los árboles. Se concluye que la taza de sobrevivencia para especies de leguminosas arbóreas forrajeras, determinan su capacidad para establecer sistemas silvopastoriles en clima templado subhúmedo en arreglos de bancos de proteína mixtos. &nbsp

Role of age and comorbidities in mortality of patients with infective endocarditis

[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Editorial

Bimestra

Editorial

3Bimestra

Fertility of mosaico (Bos taurus x Bos indicus) crossbred cows under conditions of a very dry tropical forest

Con el objeto de evaluar la fertilidad al primer servicio (FPS), al segundo servicio (FSS) y al tercer servicio (FTS) en vacas mosaico tauro-indicas en trópico muy seco, fueron analizados doscientos noventa y cuatro (294) registros de preñez pertenecientes a tres rebaños comerciales, ubicados en una zona ecológica catalogada como bosque tropical muy seco. El análisis estadístico consistió en la prueba de significación “t” student de diferencia entre dos porcentajes basada en la transformación arcoseno, que incluyó los efectos del año del parto, época del parto, rebaño, edad de la vaca al parto y predominio de la especie. Todos lo efectos fueron significativos (P<0.05) sobre la fertilidad, excepto la edad de la vaca. La FPS (x) fue de 56% para los tres años, encontrándose el menor valor (37%) para el tercer año, lo que se atribuye a la escasa precipitación durante el mismo. La FSS y FTS mostraron la misma tendencia. Los mayores valores de fertilidad global fueron observados en las épocas 3 y 4 (meses de Agosto a Diciembre), obteniéndose FTS de 36% para la época 3. El rebaño C presentó FPS de 73% y FTS de 85%; no se observaron para este parámetro diferencias (P<0.05) con el rebaño B (FTS 88%), aún cuando la edad de la vaca no afectó significativamente (P>0.05) la fertilidad global. Se observaron valores superiores en primíparas (64%) en FPS. Los valores superiores en fertilidad global fueron obtenidos para los grupos genéticos ½ tauro-índicos y los predominantes Bos taurus (FTS de 86% y 88% respectivamente).55 - 63CuatrimestralIn order to evaluate the fertility at the first (FFS), second (FSS) and third (FTS) services in crossbred cows (Bos Taurus x Bos indicus), 294 acords from pregnant cows were analyzed out of three commercial herds located at tropical forest. Statistical analysis included the “t” test for differences between two percentages based on arosin transformation by determining the effects of calving year, calving season herd, cow age calving and specie predominance. All the effects were significatives (P<0.05) on cow fertility, except for cow age. FFS average was 56% for all years; wich was attributed to little rain fall. Both FSS and FTS showed the same trend in that year. Fertility was highest from August to December, at periods three and four, by obtaining 96% FTS for period three. The herd C showed 73% FFS as well as 85% FTS, but no significant differences were found against herd B (88%); even though age of cow did not affect (P>0.05) overall fertility. Greater values were noticed on first calving cows (64% FFS). Also, higher FTS values were performed by ½ indicus cows (86%) and topcrossed tauro cows (83%)