Sexual propagation of Abies religiosa (Kunth) Cham, by immersion in water at different temperatures and periods

Objective: To increase the percentage of germination in Abies religiosa by immersion in water at different temperatures and times that the seeds will be soaked. Design/methodology/approach: A completely randomized factorial experiment was carried oud with five temperatures (10, Ta, 30, 40 and 50 °C) and 13 times expressed in seconds (10, 20, 40, 60, 600, 1200, 1800, 2400, 3000, 3600, 7200, 14400 and 2160) with a total of 65 treatments and 30 replications of each treatment. The seed were immersed in water at different temperatures and times corresponded to each treatment in order to obtain the best treatment that generated the highest percentage. Results: The best pre-germinative treatment that generated the highest germination percentage was the combination of temperature of 40 °C and a time of 7200s, obtaining 73% germination, and 14% germination as the lowest percentage in the combinations (10 °C x 20s and 10 °C x 40s), generating 26 treatments with percentages higher than 50% germination, registering a peak value of 8.56 and 11.7 days to reach the peak value. Limitations on study/implications: In the experiment, it was important to maintain the different temperatures constant, being those of longer time, lower temperature and higher temperature the most difficult to control and maintain Findings/conclusions: Abies religiosa is able to tolerate and generate acceptable germination percentages with the highest temperature used (50 °C), being one of the best temperatures, which was supposed to generate low germination percentages. Keywords: Germination, Temperature, Time, Peak valueObjective: To increase the germination percentage of Abies religiosa by immersion in water with different temperatures and periods.Design/Methodology/Approach: A completely randomized factorial experiment was carried out with five temperatures (10, Room temperature (Rt), 30, 40, and 50°C) and 13 periods expressed in seconds (10, 20, 40, 60, 600, 1200, 1800, 2400, 3000, 3600, 7200, 14400, and 21600), with a total of 65 treatments and 30 repetitions per treatment. The seeds were dipped in water with the temperatures and periods of each treatment to obtain the highest germination percentage.Results: The best pre-germination treatment (73% germination) was obtained with the combination of 40 °C and 7,200 s. Meanwhile, the treatments with the lowest percentage (14%) were the combinations 10 °C × 20 s and 10 °C × 40 s. Twenty-six treatments recorded a >50% germination, reaching a peak value of 8.56 at 11.7days. Study Limitations/Implications: Keeping the water temperature and theimmersion period constant during the experiment was more difficult in the longer treatments, with the lowest and highest temperatures.Findings/Conclusions: Abies religiosa registers acceptable germination percentages with the highest temperature (50 °C)

Field Attractants for Pachnoda interrupta Selected by Means of GC-EAD and Single Sensillum Screening

The sorghum chafer, Pachnoda interrupta Olivier (Coleoptera: Scarabaeidae: Cetoniinae), is a key pest on sorghum, Sorghum bicolor (L.) Moench (Poaceae), in Ethiopia. At present there is a lack of efficient control methods. Trapping shows promise for reduction of the pest population, but would benefit from the development of attractive lures. To find attractants that could be used for control of P. interrupta, either by mass trapping or by monitoring as part of integrated pest management, we screened headspace collections of sorghum and the highly attractive weed Abutilon figarianum Webb (Malvaceae) for antennal activity using gas chromatograph-coupled electroantennographic detection (GC-EAD). Compounds active in GC-EAD were identified by combined gas chromatography and mass spectrometry (GC-MS). Field trapping suggested that attraction is governed by a few influential compounds, rather than specific odor blends. Synthetic sorghum and abutilon odor blends were attractive, but neither blend outperformed the previously tested attractants eugenol and methyl salicylate, of which the latter also was part of the abutilon blend. The strong influence of single compounds led us to search for novel attractive compounds, and to investigate the role of individual olfactory receptor neurons (ORNs) in the perception of kairomones. We screened the response characteristics of ORNs to 82 putative kairomones in single sensillum recordings (SSR), and found a number of key ligand candidates for specific classes of ORNs. Out of these key ligand candidates, six previously untested compounds were selected for field trapping trials: anethole, benzaldehyde, racemic 2,3-butanediol, isoamyl alcohol, methyl benzoate and methyl octanoate. The compounds were selected on the basis that they activated different classes of ORNs, thus allowing us to test potential kairomones that activate large non-overlapping populations of the peripheral olfactory system, while avoiding redundant multiple activations of the same ORN type. Field trapping results revealed that racemic 2,3-butanediol is a powerful novel attractant for P. interrupta

La demostración en matemáticas. Clasificación y ejemplos en el marco de la educación secundaria

Se describe buena parte de las demostraciones matemáticas que figuran en los currículos de Enseñanza Secundaria tanto desde el punto de vista científico (verificación, sistematización) como desde el didáctico (medio de: explicación. descubrimiento y comunicación). Se propone una clasificación de las técnicas de demostración acompañadas de múltiples ejemplos. El trabajo termina con una muestra de resolución de problemas que ilustra el uso de todas las técnicas

Propedeútica clínica

Grabación de vídeos docentes para el aprendizaje de las técnicas de exploración física normalDepartamento de Medicina, Dermatología y Toxicologí