ABSTRACT Recent empirical results show that forecast combinations and cross-learning schemes are winning approaches in the time series field. Although many competition-winning combination methods - with cross-learning or not - use static weights along the forecasting horizon, we could not find extensive work about the effects of using horizon-optimized weights. This paper proposes a forecast combination framework and provides a considerably sizeable empirical investigation into the use of horizon-optimized weights, i.e., weights that may vary over the forecasting horizon. We build on cross-learning, time series clustering and cross-validation to form Horizon-Optimized Convex Combinations (HOC2) of forecasts from five methods: Automated exponential smoothing, Automated ARIMA, Theta, TBATS, and Seasonal naïve. Our combinations were tested with data from the previous M1, M3 and M4 forecast competitions, comprising 104,004 time series with different frequencies and lengths. The results shall be helpful to support future research on how horizon-optimized weights can be used interchangeably with static ones.

Resumo Nanotubos de haloisita (NTH) são nanoargilas de silicato de alumínio com estrutura naturalmente tubular. Eles são biocompatíveis e apresentam viabilidade como carreador de moléculas biologicamente ativas devido ao seu espaço interno na estrutura tubular. Neste artigo as principais características dos NTH e a obtenção de nanocompósitos poliméricos com NTH, e suas potenciais aplicações para o aperfeiçoamento das propriedades mecânicas dos polímeros e como carreador de substâncias hidrofílicas e lipofílicas são revisadas. Revisam-se os trabalhos recentes publicados sobre nanocompósitos poliméricos com NTH e apresenta-se o promissor emprego desses sistemas como carreadores, devido à sua capacidade de sustentar a liberação de fármacos em escala nanométrica, adequados para aplicação na área farmacêutica e biomédica, apresentando baixa citotoxicidade e promovendo a liberação controlada de fármacos.

Abstract Halloysite nanotubes (HNTs) are aluminosilicate nanoclay mineral which have a hollow tubular structure and occurs naturally. They are biocompatible and viable carrier for inclusion of biologically active molecules due to the empty space inside the tubular structure. In this article, the HNTs main characteristics, and the HNTs-polymeric nanocomposite formation and their potential application as improvement of the mechanical performance of polymers and entrapment of hydrophilic and lipophilic substances are summarized. Recent works covering the increment of HNTs-polymeric nanocomposites and presenting promising employment of these systems as nanosized carrier, being suitable for pharmaceutical and biomedical applications, based on earlier evidence in literature of its nature to sustain the release of loaded drugs, presenting low cytotoxicity, and providing evidence for controlled drug delivery are reviewed.

RESUMOA laminite em cavalos está frequentemente associada a distúrbios endócrinos, como a disfunção da pars intermedia da pituitária (PPID) em animais mais velhos. Exames morfológicos do tecido laminar do casco foram realizados em dois cavalos com suspeita de PPID após o óbito, os quais não apresentaram sinais clínicos de laminite. Alterações compatíveis com a laminite de origem endócrina foram observadas, como arredondamento da núcleo das células basais, alongamento e afilamento das lâminas epidérmicas secundárias e proliferação tecidual. Cavalos com PPID sem sinais clínicos de laminite podem estar acometidos por lesões do tecido laminar do casco que comprometam a integridade das interdigitações dérmico-epidérmicas e podem desenvolver a sintomatologia clínica da doença. Sugere-se que o período de desenvolvimento da laminite endócrina seja mais longo, porém estudos adicionais devem ser realizados para confirmar essa hipótese.

ABSTRACTLaminitis in horses is often associated with endocrine disorders, especially the pituitary pars intermedia dysfunction (PPID) in older animals. Morphologic exams of the laminar tissue of the hoof were performed in two horses with suspected PPID, with no clinical signs of laminitis. Changes compatible with laminitis of endocrine origin were observed, such as rounding of the nuclei of the basal cells, thinning and stretching of the secondary epidermal laminae and tissue proliferation. PPID horses with no clinical signs of laminitis may be affected by lesions of the laminar tissue of the hoof that compromise the integrity of the dermal-epidermal junction and may develop clinical symptoms of the disease. It has been suggested that the development stage of endocrine laminitis is longer, but further studies should be conducted to confirm it.

This work reports a study on the heterogeneous Fenton reaction using hematite powder (Fe2O3) in suspension for the discolouration of the reactive dye Drimarene Red X-6BN in aqueous solutions. The efficiency of the process was studied as a function of the experimental conditions: initial pH; H2O2 dose; and hematite powder concentration; all of which showed a strong effect on the reaction kinetics. Under the best experimental conditions: pH = 2.5; H2O2 dose = 800 mg/L; and [Hematite] = 20 g/L, it was possible to remove about 99% of the initial colour in 120 minutes in a batch reaction at 25ºC. The analysis of the kinetic results suggests that the reaction is initiated by heterogeneous generation of free radicals on the hematite surface, but as soluble iron (III) and iron (II) species are released into the solution during the course of the reaction, a simultaneous homogeneous Fenton reaction step propagates and contributes to the overall reaction.

The aim of this study was to test the hypothesis of differences in performance including differences in ST-T wave changes between healthy men and women submitted to an exercise stress test. Two hundred (45.4%) men and 241 (54.6%) women (mean age: 38.7 ± 11.0 years) were submitted to an exercise stress test. Physiologic and electrocardiographic variables were compared by the Student t-test and the chi-square test. To test the hypothesis of differences in ST-segment changes, data were ranked with functional models based on weighted least squares. To evaluate the influence of gender and age on the diagnosis of ST-segment abnormality, a logistic model was adjusted; P < 0.05 was considered to be significant. Rate-pressure product, duration of exercise and estimated functional capacity were higher in men (P < 0.05). Sixteen (6.7%) women and 9 (4.5%) men demonstrated ST-segment upslope ≥0.15 mV or downslope ≥0.10 mV; the difference was not statistically significant. Age increase of one year added 4% to the chance of upsloping of segment ST ≥0.15 mV or downsloping of segment ST ≥0.1 mV (P = 0.03; risk ratio = 1.040, 95% confidence interval (CI) = 1.002-1.080). Heart rate recovery was higher in women (P < 0.05). The chance of women showing an increase of systolic blood pressure ≤30 mmHg was 85% higher (P = 0.01; risk ratio = 1.85, 95%CI = 1.1-3.05). No significant difference in the frequency of ST-T wave changes was observed between men and women. Other differences may be related to different physical conditioning.

Para definir la técnica de medición de potencial hídrico en el cultivo del guayabo (Psidium guajava L.) se llevó a cabo una investigación en la finca "Los Cienegos" del estado Zulia. Se seleccionaron 8 plantas de guayabo sembradas a pié franco y 8 plantas injertadas de 3 años de edad, sembradas a distancia de 5 m x 5 m, con manejo agronómico similar. Las variables estudiadas fueron el potencial hídrico del tallo (Yt) y el potencial hídrico de la hoja (Yh). Para la medición del potencial hídrico del tallo se utilizaron los criterios empleado por Begg y Turner (1970) en el cultivo del tabaco (Nicotina tabaco L.) y McCutchuam y Shackeland (1992) en el cultivo del durazno (Prunus domestica L). Para la medición del potencial hídrico de la hoja, se empleó el criterio establecido para plantas vasculares por Scholander (1965). Los resultados demostraron que existe poca diferencia entre los potenciales hídricos del tallo y de la hoja para las primeras horas de la mañana, mientras que se registraron diferencias de mayor magnitud en horas del mediodía, entre las 12 y las 14 horas. La variabilidad en los potenciales de la hoja durante este último periodo, también fue mayor que los potenciales del tallo. Después de las 14 horas, los valores de potenciales se estabilizaron y comenzó el proceso de rehidratación de la planta.

This study was carried out for the purpose of defining a reliable technique for measuring water potential of guava trees (Psidium guajava L.). Eight self-rooted and eight grafted three years old trees were selected at "Los Ciénegos" farm, Zulia state, planted at a distance of 5 m x 5 m, with similar agronomic management. Leaf (yL) and stem (yS) water potentials were quantified using three different techniques. The Begg and Turner (1970) criteria for tobacco was utilized for the measurement of stem potential as well as the McCutcham and Shackeland (1992) criteria, applied to tobacco (Nicotiana tabacum L.) and peach (Prunus domestica L.), respectively. While the Scholander (1965) criteria was applied for measuring yL. Results showed that there was little difference between yS and yL early in the morning, but it greater differences occured at noon, specifically between the 12 (noon) and 14 (2PM)hours. More over, a greater variability was found in yL as compared to yS during this period. After 14 hours (2PM), water potential values became stabilized and the plant re-hydration process began.

Se estudió la dinámica de crecimiento en frutos de guayaba tipo Criolla Roja, en una parcela experimental ubicada en el Centro Fruticola del Zulia-CORPOZULIA del municipio Mara del estado Zulia, Venezuela. Se marcaron 6572 botones florales en 24 árboles uniformes. Se realizaron 17 muestreos destructivos semanalmente desde botón floral hasta madurez fisiológica. Se utilizó la tasa de crecimiento relativo (TCR) como variable fisiológica marcadora del crecimiento entre las etapas. Se empleó un diseño experimental de bloques al azar, con 17 edades como tratamientos y cuatro repeticiones, constituidas por seis plantas cada una. Se usaron estadísticas descriptivas, análisis de varianza y pruebas de medias por Tukey. El tiempo transcurrido entre preantesis y antesis fue de 7 días, y 15 días desde la antesis al cuajado. La duración del ciclo desde el cuajado hasta la madurez fisiológica fue de 119 días. La curva de crecimiento acumulado para la masa fresca y seca, diámetro polar y ecuatorial coincidió con una doble sigmoide. La etapa I de la curva se prolongó hasta los 70 días. La masa fresca y seca presentaron una cinética similar y la mayor TCR de los frutos se evidenció a nivel de las etapas I y III, mientras que en la etapa II disminuyó notablemente.

Growth dynamics of Criolla Roja type guava fruits were studied in an experimental plot, located in Centro Fruticola del Zulia-CORPOZULIA in Mara county Zulia state, Venezuela. 6572 floral blossoms were marked on 24 trees. Each week, 17 destructive samplings were made starting from the floral blossom stage up to the physiological fruit ripening stage. Relative growth rates (RGR) were used as a physiological parameter indicator of the growth between stages. A randomized block design was used, taking 17 ages as treatments and four repetitions of six plants each. Simple statistics, ANOVA and Tukey's Student Range were applied. The time lapsed between preanthesis and anthesis was seven days, and 15 days from antesis to fruit-set. The cycle from fruit-set to physiological maturity lasted 119 days. The accumulated growth curve for fresh and dry mass, polar and equatorial diameter, corresponded to a double sigmoide. Stage I of the curve was extended to 70 days. Fresh and dry mass presented similar kinetics and the greatest RGR occurred at the level of stages I and III, while it decreased significantly in stage II.