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Breeding and micropropagation of Phalaenopsis orchids
(2025-11-04) Chen, Fure-Chyi; Huang, Jian-Zhi; Bolaños Villegas, Pablo Alberto
The procedure for breeding Phalaenopsis orchids involves several key steps: setting breeding objectives, cross-hybridization, in vitro seed germination, cultivating seedlings through various growth stages, inducing the formation of floral spikes and flowering, selecting desirable lines, and using floral stalk node culture for micropropagation. The global orchid market features numerous commercial Phalaenopsis hybrids, with new cultivars continually emerging each year. Breeding goals for new hybrids now include achieving polyploidy, splashy color patterns, vivid floral fragrances, and growth of multiple flower spikes. To cut costs, high energy efficiency during production is now a priority. This efficiency has led to creating hybrids between Phalaenopsis and the Vanda alliance that can flower easily in simple greenhouses without air conditioning. This chapter outlines the processes of in vitro seed germination, embryo rescue, flower stalk node culture, and micropropagation of Phalaenopsis to provide an outline for a comprehensive breeding scheme. We hope this exercise in genetics, biotechnology, and engineering will be a useful guide for commercial orchid breeders worldwide.
Genetics and propagation of Sobralia orchids
(2025-11-05) Bolaños Villegas, Pablo Alberto
Sobralia is a genus of terrestrial orchids native to the tropical regions of the Americas, distinguished by the fleeting yet striking beauty of its large and symmetrical flowers. Limited efforts have been made in plant breeding within this genus, resulting in most specimens being sourced from wild populations. Research conducted at Lankester Gardens indicates that in vitro seed germination rates are high, suggesting the potential for hybridizing and propagating species with advantageous traits such as extended flower longevity and fragrance. Future research may concentrate on the greenhouse acclimatization of tissue culture plants and polyploidization, aiming to establish a robust pipeline of hybrids exhibiting vibrant flower colors.
Concurrent training reduces depressive symptoms in Mexican female older adults
(2020-07) Canton Martínez, Ermilo; Rentería, Iván; Moncada Jiménez, José; García Suárez, Patricia Concepcion; Gómez Miranda, Luis Mario; de Paz Fernández, José Antonio; Jiménez Maldonado, Alberto
Purpose: To determine the effect of a concurrent-training exercise program (CTEP) on mild depression in Mexican female OA. A secondary aim was to determine the correlation between physical function, body composition and depressive symptoms in OA following a CTEP. Methods: Twenty-one females (age= 64.0 ± 5.38 yr., weight= 72.0 ± 12.6 kg, BMI= 29.0 ± 4.7 kg/m2) participated in the study. Before (Pre) and after (Post) the CTEP, participants were measured on depression by the Hamilton Depression Rating Scale (HAM-D), body fat, muscle mass [MM]), physical function by the Senior Fitness Test, and aerobic capacity by the 6-min walking test (6MWT). The CTEP consisted in two days of aerobic exercise and one day of resistance training performed for 50-min at moderate intensity (12 to 14 on Borg’s RPE scale) for 12-weeks. Paired t-tests were computed to compare pre- to post-CTEP effects, and Spearman correlations studied the association between body composition, physical function and depression scores using the GraphPad PRISM 5.0 software. Results: The CTEP reduced HAM-D scores (Pre= 15.7 ± 4.5 vs. Post= 10.3 ± 5.3 pts., p=0.0001), improved upper-body strength (Pre= 15.1 ± 2.6 vs. Post= 18.9 ± 3.0 reps, p=0.0001), lower-body strength (Pre= 12.0 ± 2.4 vs. Post= 14.5 ± 2.9 reps, p= 0.0001), agility (Pre= 6.5 ±0.9 vs. Post= 6.0 ± 0.9 s, p=0.0001), and MM (Pre= 21.8 ± 2.9 vs. Post= 22.26 ± 3.1 kg, p=0.002). No significant changes were found in aerobic capacity (Pre= 587.9 ± 164.4 vs. Post= 619.6 ±144.9 m, p=0.06) and body fat (Pre= 31.0 ± 8.8 vs. Post= 30.8 ± 9.1%, p > 0.05). The HAM-D scores were inversely correlated with upper-body strength (r= -0.53, p=0.002) and lower-body strength (r= -0.64, p= 0.002), and directly correlated to agility (r= 0.50, p= 0.0004). Conclusions: A CTEP reduced depressive symptoms in Mexican female OA in spite of lack of changes in body composition. The increased physical function relates to a reduction in depressive symptoms; thus, highlighting the importance of improving functionality in OA.
Bioimpedance phase angle reliability in Mexican college students
(2020-07) Aburto Corona, Jorge Alberto; Torres Hernández, Alan D.; Gómez Miranda, Luis Mario; Chacón Araya, Yamileth; Moncada Jiménez, José
Purpose: To determine phase angle reliability in Mexican college students. Methods: College students from the city of Tijuana, México, were recruited for this study. Volunteers were 26 males (Age = 22.7 ± 3.1 yr., Height = 172.8 ± 5.6 cm, Weight = 70.9 ± 11.7 kg) and 26 females (Age = 21.1 ± 2.2 yr., Height = 159.0 ± 7.1 cm, Weight = 60.8 ± 8.6kg). Participants arrived euhydrated to the testing session (Urine specific gravity = 1.005 ± 0.003) and were measured on a multi-frequency InBody 770 BIA device in two occasions separated by five minutes of seated resting. Body weight, %fat mass, muscle mass (kg) and PA were recorded and analyzed by repeated measures 2 (gender) x 2 (measures) ANCOVA, using hydration status and age as covariates. Intraclass correlation coefficient (ICC) and 95% confidence interval were used to determine reliability between measures. Results: Gender differences were found on PA (Males = 6.8 ± 0.1 vs. Females = 5.9 ± 0.1, p ≤ 0.0001), and muscle mass (Males = 31.9 ± 0.7 vs. Females = 23.2 ± 0.7 kg, p ≤ 0.0001). Significant (p ≤ 0.0001 for all) ICC reliability coefficients were found between pre- to post-measures of PA (r = 0.998, 95%CI = 0.996 to 0.999), %fat (r = 0.999, 95%CI = 0.998 to 1.00) and muscle mass (r = 1.00, 95%CI= 1.00 to 1.00). Conclusion: Young college students showed reliable BIA PA, muscle mass and %fat values following five minutes of seated resting. Mexican males showed higher muscle mass and PA than women after controlling for the influence of hydration and age.
Modelos de Aprendizaje Automático para el Pronóstico de las tasas de interés de los bonos del Tesoro de los Estados Unidos en el Banco Central de Costa Rica
(2025) Valverde Montero, Emilio; Ramos Esquivel, Mario Alberto
Este proyecto se enfoca en el diseño e implementación de modelos predictivos basados en aprendizaje automático para estimar la curva de rendimiento de los bonos del Tesoro de los Estados Unidos, con aplicación directa en la gestión financiera del Banco Central de Costa Rica (BCCR).
La investigación partió de un análisis del entorno económico global, el rol de los bancos centrales en la administración de reservas internacionales, y la necesidad de mejorar la precisión en la proyección de tasas de interés como insumo clave para la toma de decisiones estratégicas.
Se identificaron oportunidades para sustituir el enfoque cualitativo actual por métodos cuantitativos que incorporen modelos científicos de predicción y permitan mejorar la objetividad, exactitud y eficiencia del proceso decisional.
A partir de esto, se desarrollaron tres modelos basados en redes neuronales: RNN, LSTM y GRU. Estas arquitecturas fueron entrenadas con datos históricos de tasas de interés, indicadores técnicos y variables macroeconómicas, con el objetivo de estimar de forma precisa los rendimientos de bonos en distintos plazos. Los resultados mostraron un desempeño notable, con errores bajos y una capacidad efectiva de replicar la forma y dinámica de la curva de rendimientos observada.
Además del análisis técnico, se evaluó el impacto práctico de los modelos en la gestión financiera institucional a través de dos casos prácticos uno de optimización de portafolio y otro de emisión soberana. En el caso del portafolio de inversión, el modelo optimizado superó consistentemente al índice de referencia en todos los escenarios evaluados y en el ejercicio de emisión de deuda, las proyecciones del modelo permitieron identificar ventanas de oportunidad para colocar bonos en los tramos más eficientes de la curva, logrando una reducción sistemática del costo financiero proyectado con ahorros anuales entre 2.6% y 4.4%.