ANTECEDENTES Y OBJETIVO: El incumplimiento terapéutico con los corticoides inhalados (CI) es frec... more ANTECEDENTES Y OBJETIVO: El incumplimiento terapéutico con los corticoides inhalados (CI) es frecuente en los pacientes con asma. Se ha señalado que la elección del dispensador por el paciente facilitaría la solución del problema. El FSI-10 (Evaluación de la Satisfacción con el Inhalador) es un cuestionario autorrellenable que valora las opiniones sobre comodidad, dificultad, transportabilidad y manejabilidad de los dispositivos para CI. El objetivo de este trabajo ha sido definir las propiedades métricas del FSI-10 y comparar, mediante este inventario, la satisfacción y las preferencias de los pacientes con asma respecto a 3 dispositivos para CI: Turbuhaler ® (T), Accuhaler ® (A) y Novolizer ® (N). PACIENTES Y MÉTODOS: Hemos realizado un estudio observacional, prospectivo y multicéntrico en 112 asmáticos (64 mujeres; edad media ± desviación estándar: 37 ± 22 años) estables y tratados regularmente con CI. Se les explicó la técnica de utilización de los dispositivos a evaluar y, aleatoriamente, se asignó el orden en que debían emplearlos. Usaron los dispositivos durante períodos de 7 días, tras los cuales cumplimentaron el FSI-10. Completado el protocolo, todos ellos expresaron el grado de preferencia por los dispositivos empleados.
Lack of adherence to inhaled corticosteroid therapy is common in patients with asthma, and it has... more Lack of adherence to inhaled corticosteroid therapy is common in patients with asthma, and it has been suggested that allowing patients to choose their own inhalers would resolve this problem. The FSI-10 (Feeling of Satisfaction with Inhaler) is a self-completed questionnaire to assess patient opinions regarding ease or difficulty of use, portability, and usability of devices for delivery of inhaled corticosteroids. The aim of this study was to define the measurement properties of the FSI-10 questionnaire and to use this inventory to compare satisfaction and preferences of patients with asthma regarding 3 different devices for delivery of inhaled corticosteroids: Turbuhaler, Accuhaler, and Novolizer.We performed a multicenter, prospective, observational study in 112 stable asthmatic patients (64 women; mean [SD] age, 37 [22] years) treated on a regular basis with inhaled corticosteroids. The use of the devices was explained to the patients and the order in which they should be used in each case was randomly assigned. The devices were used for 7-day periods and at the end of each the FSI-10 questionnaire was completed for the device used. Once the protocol was completed, patients stated their preference for the different devices used.The FSI-10 was easily understood and rapidly completed, and it exhibited acceptable measurement properties. Factor analysis showed that the measure was unidimensional. Although acceptance of all 3 devices assessed was reasonable, the FSI-10 questionnaire detected significant differences between them: Turbuhaler and Novolizer scored higher than Accuhaler on a number of questions. This preference is partly explained by Turbuhaler having been the device that was commonly used by the patients prior to the study. However, the highest scoring and most often preferred inhaler in patients under 16 years of age was the Novolizer, even though the Turbuhaler had also usually been used by those patients prior to the study.The FSI-10 is a useful instrument for assessing the degree of satisfaction of asthmatic patients regarding available inhalation devices. It is easy to understand and complete, and able to identify differences in patient satisfaction with the different inhalers.El incumplimiento terapéutico con los corticoides inhalados (CI) es frecuente en los pacientes con asma. Se ha señalado que la elección del dispensador por el paciente facilitaría la solución del problema. El FSI-10 (Evaluación de la Satisfacción con el Inhalador) es un cuestionario autorrellenable que valora las opiniones sobre comodidad, dificultad, transportabilidad y manejabilidad de los dispositivos para CI. El objetivo de este trabajo ha sido definir las propiedades métricas del FSI-10 y comparar, mediante este inventario, la satisfacción y las preferencias de los pacientes con asma respecto a 3 dispositivos para CI: Turbuhaler® (T), Accuhaler® (A) y Novolizer® (N).Hemos realizado un estudio observacional, prospectivo y multicéntrico en 112 asmáticos (64 mujeres; edad media ± desviación estándar: 37 ± 22 años) estables y tratados regularmente con CI. Se les explicó la técnica de utilizatión de los dispositivos a evaluar y, aleatoriamente, se asignó el orden en que debían emplearlos. Usaron los dispositivos durante períodos de 7 días, tras los cuales cumplimentaron el FSI-10. Completado el protocolo, todos ellos expresaron el grado de preferencia por los dispositivos empleados.El FSI-10 resultó fácil de comprender y rápido de cumplimentar, y mostró propiedades métricas aceptables. El analisis factorial exploratorio muestra la unidimensionalidad de la medida. La aceptacion de los 3 dispositivos evaluados fue razonable, pero el FSI-10 detect» diferencias signiflcativas entre ellos: los sistemas T y N se valoraron mejor que A en bastantes preguntas del cuestionario. Esta pre-ferencia responde en parte al hecho de que T era el dispositi-vo comunmente utilizado con anterioridad por los pacientes. Sin embargo, para los menores de 16 afios el inhalador prefe-rido y mejor puntuado fue N, a pesar de que en este subgrupo tambien era el T el habitualmente manejado.El FSI-10 es un instrumento util para evaluar el grado de satisfaction del paciente asmatico con los dispositivos de inhalacion disponibles. Es comprensible, de facil manejo y capaz de identificar diferencias de satisfaccion entre distintos inhaladores.
Fundamento: Registrar los hábitos alimenticios exige de un método válido y fiable. El objetivo de... more Fundamento: Registrar los hábitos alimenticios exige de un método válido y fiable. El objetivo del estudio es validar el cuestionario de frecuencia de consumo de alimentos CDC-FFQ, que es una adaptación de otro cuestionario, para estudiar la alimentación de la población adulta de Canarias.
In the present research, we studied the effect of the administration of melatonin or S-adenosyl-l... more In the present research, we studied the effect of the administration of melatonin or S-adenosyl-l-methionine (S-AMe) on oxidative stress and hepatic cholestasis produced by double ligature of the extra-hepatic biliary duct (LBD) in adult male Wistar rats. Hepatic oxidative stress was evaluated by the changes in the amount of lipid peroxides and by the reduced glutathione content (GSH) in lysates of erythrocytes and homogenates of hepatic tissue. The severity of the cholestasis and hepatic injury were determined by the changes in the plasma enzyme activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AP), g-glutamyl-transpeptidase (GGT), and levels of albumin, total bilirubin (TB) and direct bilirubin (DB). Either melatonin or S-AMe were administered daily 3 days before LBD, and for 10 days after biliary obstruction. LDB caused highly significant increases in plasma enzyme activities and in bilirubin and lipid peroxides levels in erythrocytes and hepatic tissue. At the same time, this procedure produced a notable decrease in the GSH pools in these biological media. Both melatonin and S-AMe administration were effective as antioxidants and hepatoprotective substances, although the protective effects of melatonin were superior; it prevented the GSH decrease and reduced significantly the increases in enzyme activities and lipid peroxidation products produced by biliary ligature. S-AMe did not modify the increased GGT activity nor did it decrease greatly the TB levels (43% melatonin vs. 14% S-AMe). However, S-AMe was effective in preventing the loss of GSH in erythrocytes and hepatic tissue, as was melatonin. The obtained data permit the following conclusions. First, the LDB models cause marked hepatic oxidative stress. Second, the participation of free radicals of oxygen in the pathogenecity and severity of cholestasis produced by the acute obstruction of the extra-hepatic biliary duct is likely. Third, the results confirm the function of S-AMe as an antioxidant and hepatoprotector. Finally, melatonin is far more potent and provides superior protection as compared to S-AMe. Considering the decrease in oxidative stress and the intensity of cholestasis, these findings have interesting clinical implications for melatonin as a possible therapeutic agent in biliary cholestasis and parenchymatous liver injury.
ANTECEDENTES Y OBJETIVO: El incumplimiento terapéutico con los corticoides inhalados (CI) es frec... more ANTECEDENTES Y OBJETIVO: El incumplimiento terapéutico con los corticoides inhalados (CI) es frecuente en los pacientes con asma. Se ha señalado que la elección del dispensador por el paciente facilitaría la solución del problema. El FSI-10 (Evaluación de la Satisfacción con el Inhalador) es un cuestionario autorrellenable que valora las opiniones sobre comodidad, dificultad, transportabilidad y manejabilidad de los dispositivos para CI. El objetivo de este trabajo ha sido definir las propiedades métricas del FSI-10 y comparar, mediante este inventario, la satisfacción y las preferencias de los pacientes con asma respecto a 3 dispositivos para CI: Turbuhaler ® (T), Accuhaler ® (A) y Novolizer ® (N). PACIENTES Y MÉTODOS: Hemos realizado un estudio observacional, prospectivo y multicéntrico en 112 asmáticos (64 mujeres; edad media ± desviación estándar: 37 ± 22 años) estables y tratados regularmente con CI. Se les explicó la técnica de utilización de los dispositivos a evaluar y, aleatoriamente, se asignó el orden en que debían emplearlos. Usaron los dispositivos durante períodos de 7 días, tras los cuales cumplimentaron el FSI-10. Completado el protocolo, todos ellos expresaron el grado de preferencia por los dispositivos empleados.
Pituitary adenomas are benign neoplasias, but they may behave locally more aggressive. Methods: T... more Pituitary adenomas are benign neoplasias, but they may behave locally more aggressive. Methods: The present study analyzes the significance of proliferative activity by Ki-67 staining in a series of 107 pituitary adenomas. Results: The mean proliferative activity rate was 1.99% (range 0%-18%) and the majority (81%) showed Ki-67 <3%. We showed a trend towards a higher Ki-67 in adenomas with extrasellar extension, hormonal subtype (prolactinomas and gonadotroph cell adenomas), male gender and younger age. However, no significant differences were found between Ki-67 and mitochondrial or microvascular densities, functional activity or recurrence. Conclusions: We conclude that the proliferative activity evaluated by Ki-67 can define a subset of pituitary adenomas with a more aggressive behavior.
The main objective of this study is to establish the level of pollen abortion prior to its releas... more The main objective of this study is to establish the level of pollen abortion prior to its release from the anther in species of Chenopodiaceae in marsh habitats and to compare this level among the taxons, locations and positions of the flowers in the dichasium and the relative positions of the anthers. We established the level of nonfunctional pollen formation in 39 samples belonging to 10 species, using lactophenol cotton blue staining. Aborted pollen grains were found to be significantly smaller than normal ones. The results revealed differences in the percentage of normal grains among different species and tribes studied: Atripliceae (56.1 ± 27.1%), Salicornieae (80.36 ± 16.52%), Suaedeae (54.7 ± 31.2%) and Salsoleae (32.5 ± 25.7%). In some species there were significant differences among the populations studied, but in species of Saliconieae we found no differences either between different positions in the dicasia or in the anther. In the tribes Suaedeae and Salsoleae, we postulate the existence of a system that maintains different levels of partial male sterility among individuals in the populations, which would reduce the autogamous fruit set rate and favor the cross-pollination rates of sterile male individuals. We base this on high intrapopulation variability at those levels, on the constancy with which they are presented in the different populations studied, and on the lack of interannual differences.
The main objective of this study is to establish the level of pollen abortion prior to its releas... more The main objective of this study is to establish the level of pollen abortion prior to its release from the anther in species of Chenopodiaceae in marsh habitats and to compare this level among the taxons, locations and positions of the flowers in the dichasium and the relative positions of the anthers. We established the level of nonfunctional pollen formation in 39 samples belonging to 10 species, using lactophenol cotton blue staining. Aborted pollen grains were found to be significantly smaller than normal ones. The results revealed differences in the percentage of normal grains among different species and tribes studied: Atripliceae (56.1 ± 27.1%), Salicornieae (80.36 ± 16.52%), Suaedeae (54.7 ± 31.2%) and Salsoleae (32.5 ± 25.7%). In some species there were significant differences among the populations studied, but in species of Saliconieae we found no differences either between different positions in the dicasia or in the anther. In the tribes Suaedeae and Salsoleae, we postulate the existence of a system that maintains different levels of partial male sterility among individuals in the populations, which would reduce the autogamous fruit set rate and favor the cross-pollination rates of sterile male individuals. We base this on high intrapopulation variability at those levels, on the constancy with which they are presented in the different populations studied, and on the lack of interannual differences.
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
High dense bulk specimens of 0.55% C steel with ferritic grain sizes within the nanocrystalline a... more High dense bulk specimens of 0.55% C steel with ferritic grain sizes within the nanocrystalline and ultrafine regimes have been produced from ball-milled iron powder through the warm consolidation process. The microstructure, the mechanical properties and the strain rate sensitivity parameter (m) were investigated for the different grain sizes obtained. A constant decrease of m was found as the grain size decreases within the ultrafine regime. In the nanocrystalline regime, on the contrary, as the grain size decreases a slight increase of m was observed.
The strain rate sensitivity of three steels with carbon contents ranging from 0.05 to 0.55 wt.% h... more The strain rate sensitivity of three steels with carbon contents ranging from 0.05 to 0.55 wt.% has been determined by nanoindentation and compression tests in the nanocrystalline and ultrafine-grained ranges. Samples were obtained by warm consolidation from milled powders. In the nanocrystalline range the steel with higher carbon content was found to be slightly rate sensitive, which means that the presence of carbon involves a change in the deformation mechanism of body-centered cubic iron, resulting in grain boundaries contributing to the plasticity.
ANTECEDENTES Y OBJETIVO: El incumplimiento terapéutico con los corticoides inhalados (CI) es frec... more ANTECEDENTES Y OBJETIVO: El incumplimiento terapéutico con los corticoides inhalados (CI) es frecuente en los pacientes con asma. Se ha señalado que la elección del dispensador por el paciente facilitaría la solución del problema. El FSI-10 (Evaluación de la Satisfacción con el Inhalador) es un cuestionario autorrellenable que valora las opiniones sobre comodidad, dificultad, transportabilidad y manejabilidad de los dispositivos para CI. El objetivo de este trabajo ha sido definir las propiedades métricas del FSI-10 y comparar, mediante este inventario, la satisfacción y las preferencias de los pacientes con asma respecto a 3 dispositivos para CI: Turbuhaler ® (T), Accuhaler ® (A) y Novolizer ® (N). PACIENTES Y MÉTODOS: Hemos realizado un estudio observacional, prospectivo y multicéntrico en 112 asmáticos (64 mujeres; edad media ± desviación estándar: 37 ± 22 años) estables y tratados regularmente con CI. Se les explicó la técnica de utilización de los dispositivos a evaluar y, aleatoriamente, se asignó el orden en que debían emplearlos. Usaron los dispositivos durante períodos de 7 días, tras los cuales cumplimentaron el FSI-10. Completado el protocolo, todos ellos expresaron el grado de preferencia por los dispositivos empleados.
Lack of adherence to inhaled corticosteroid therapy is common in patients with asthma, and it has... more Lack of adherence to inhaled corticosteroid therapy is common in patients with asthma, and it has been suggested that allowing patients to choose their own inhalers would resolve this problem. The FSI-10 (Feeling of Satisfaction with Inhaler) is a self-completed questionnaire to assess patient opinions regarding ease or difficulty of use, portability, and usability of devices for delivery of inhaled corticosteroids. The aim of this study was to define the measurement properties of the FSI-10 questionnaire and to use this inventory to compare satisfaction and preferences of patients with asthma regarding 3 different devices for delivery of inhaled corticosteroids: Turbuhaler, Accuhaler, and Novolizer.We performed a multicenter, prospective, observational study in 112 stable asthmatic patients (64 women; mean [SD] age, 37 [22] years) treated on a regular basis with inhaled corticosteroids. The use of the devices was explained to the patients and the order in which they should be used in each case was randomly assigned. The devices were used for 7-day periods and at the end of each the FSI-10 questionnaire was completed for the device used. Once the protocol was completed, patients stated their preference for the different devices used.The FSI-10 was easily understood and rapidly completed, and it exhibited acceptable measurement properties. Factor analysis showed that the measure was unidimensional. Although acceptance of all 3 devices assessed was reasonable, the FSI-10 questionnaire detected significant differences between them: Turbuhaler and Novolizer scored higher than Accuhaler on a number of questions. This preference is partly explained by Turbuhaler having been the device that was commonly used by the patients prior to the study. However, the highest scoring and most often preferred inhaler in patients under 16 years of age was the Novolizer, even though the Turbuhaler had also usually been used by those patients prior to the study.The FSI-10 is a useful instrument for assessing the degree of satisfaction of asthmatic patients regarding available inhalation devices. It is easy to understand and complete, and able to identify differences in patient satisfaction with the different inhalers.El incumplimiento terapéutico con los corticoides inhalados (CI) es frecuente en los pacientes con asma. Se ha señalado que la elección del dispensador por el paciente facilitaría la solución del problema. El FSI-10 (Evaluación de la Satisfacción con el Inhalador) es un cuestionario autorrellenable que valora las opiniones sobre comodidad, dificultad, transportabilidad y manejabilidad de los dispositivos para CI. El objetivo de este trabajo ha sido definir las propiedades métricas del FSI-10 y comparar, mediante este inventario, la satisfacción y las preferencias de los pacientes con asma respecto a 3 dispositivos para CI: Turbuhaler® (T), Accuhaler® (A) y Novolizer® (N).Hemos realizado un estudio observacional, prospectivo y multicéntrico en 112 asmáticos (64 mujeres; edad media ± desviación estándar: 37 ± 22 años) estables y tratados regularmente con CI. Se les explicó la técnica de utilizatión de los dispositivos a evaluar y, aleatoriamente, se asignó el orden en que debían emplearlos. Usaron los dispositivos durante períodos de 7 días, tras los cuales cumplimentaron el FSI-10. Completado el protocolo, todos ellos expresaron el grado de preferencia por los dispositivos empleados.El FSI-10 resultó fácil de comprender y rápido de cumplimentar, y mostró propiedades métricas aceptables. El analisis factorial exploratorio muestra la unidimensionalidad de la medida. La aceptacion de los 3 dispositivos evaluados fue razonable, pero el FSI-10 detect» diferencias signiflcativas entre ellos: los sistemas T y N se valoraron mejor que A en bastantes preguntas del cuestionario. Esta pre-ferencia responde en parte al hecho de que T era el dispositi-vo comunmente utilizado con anterioridad por los pacientes. Sin embargo, para los menores de 16 afios el inhalador prefe-rido y mejor puntuado fue N, a pesar de que en este subgrupo tambien era el T el habitualmente manejado.El FSI-10 es un instrumento util para evaluar el grado de satisfaction del paciente asmatico con los dispositivos de inhalacion disponibles. Es comprensible, de facil manejo y capaz de identificar diferencias de satisfaccion entre distintos inhaladores.
Fundamento: Registrar los hábitos alimenticios exige de un método válido y fiable. El objetivo de... more Fundamento: Registrar los hábitos alimenticios exige de un método válido y fiable. El objetivo del estudio es validar el cuestionario de frecuencia de consumo de alimentos CDC-FFQ, que es una adaptación de otro cuestionario, para estudiar la alimentación de la población adulta de Canarias.
In the present research, we studied the effect of the administration of melatonin or S-adenosyl-l... more In the present research, we studied the effect of the administration of melatonin or S-adenosyl-l-methionine (S-AMe) on oxidative stress and hepatic cholestasis produced by double ligature of the extra-hepatic biliary duct (LBD) in adult male Wistar rats. Hepatic oxidative stress was evaluated by the changes in the amount of lipid peroxides and by the reduced glutathione content (GSH) in lysates of erythrocytes and homogenates of hepatic tissue. The severity of the cholestasis and hepatic injury were determined by the changes in the plasma enzyme activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AP), g-glutamyl-transpeptidase (GGT), and levels of albumin, total bilirubin (TB) and direct bilirubin (DB). Either melatonin or S-AMe were administered daily 3 days before LBD, and for 10 days after biliary obstruction. LDB caused highly significant increases in plasma enzyme activities and in bilirubin and lipid peroxides levels in erythrocytes and hepatic tissue. At the same time, this procedure produced a notable decrease in the GSH pools in these biological media. Both melatonin and S-AMe administration were effective as antioxidants and hepatoprotective substances, although the protective effects of melatonin were superior; it prevented the GSH decrease and reduced significantly the increases in enzyme activities and lipid peroxidation products produced by biliary ligature. S-AMe did not modify the increased GGT activity nor did it decrease greatly the TB levels (43% melatonin vs. 14% S-AMe). However, S-AMe was effective in preventing the loss of GSH in erythrocytes and hepatic tissue, as was melatonin. The obtained data permit the following conclusions. First, the LDB models cause marked hepatic oxidative stress. Second, the participation of free radicals of oxygen in the pathogenecity and severity of cholestasis produced by the acute obstruction of the extra-hepatic biliary duct is likely. Third, the results confirm the function of S-AMe as an antioxidant and hepatoprotector. Finally, melatonin is far more potent and provides superior protection as compared to S-AMe. Considering the decrease in oxidative stress and the intensity of cholestasis, these findings have interesting clinical implications for melatonin as a possible therapeutic agent in biliary cholestasis and parenchymatous liver injury.
ANTECEDENTES Y OBJETIVO: El incumplimiento terapéutico con los corticoides inhalados (CI) es frec... more ANTECEDENTES Y OBJETIVO: El incumplimiento terapéutico con los corticoides inhalados (CI) es frecuente en los pacientes con asma. Se ha señalado que la elección del dispensador por el paciente facilitaría la solución del problema. El FSI-10 (Evaluación de la Satisfacción con el Inhalador) es un cuestionario autorrellenable que valora las opiniones sobre comodidad, dificultad, transportabilidad y manejabilidad de los dispositivos para CI. El objetivo de este trabajo ha sido definir las propiedades métricas del FSI-10 y comparar, mediante este inventario, la satisfacción y las preferencias de los pacientes con asma respecto a 3 dispositivos para CI: Turbuhaler ® (T), Accuhaler ® (A) y Novolizer ® (N). PACIENTES Y MÉTODOS: Hemos realizado un estudio observacional, prospectivo y multicéntrico en 112 asmáticos (64 mujeres; edad media ± desviación estándar: 37 ± 22 años) estables y tratados regularmente con CI. Se les explicó la técnica de utilización de los dispositivos a evaluar y, aleatoriamente, se asignó el orden en que debían emplearlos. Usaron los dispositivos durante períodos de 7 días, tras los cuales cumplimentaron el FSI-10. Completado el protocolo, todos ellos expresaron el grado de preferencia por los dispositivos empleados.
Pituitary adenomas are benign neoplasias, but they may behave locally more aggressive. Methods: T... more Pituitary adenomas are benign neoplasias, but they may behave locally more aggressive. Methods: The present study analyzes the significance of proliferative activity by Ki-67 staining in a series of 107 pituitary adenomas. Results: The mean proliferative activity rate was 1.99% (range 0%-18%) and the majority (81%) showed Ki-67 <3%. We showed a trend towards a higher Ki-67 in adenomas with extrasellar extension, hormonal subtype (prolactinomas and gonadotroph cell adenomas), male gender and younger age. However, no significant differences were found between Ki-67 and mitochondrial or microvascular densities, functional activity or recurrence. Conclusions: We conclude that the proliferative activity evaluated by Ki-67 can define a subset of pituitary adenomas with a more aggressive behavior.
The main objective of this study is to establish the level of pollen abortion prior to its releas... more The main objective of this study is to establish the level of pollen abortion prior to its release from the anther in species of Chenopodiaceae in marsh habitats and to compare this level among the taxons, locations and positions of the flowers in the dichasium and the relative positions of the anthers. We established the level of nonfunctional pollen formation in 39 samples belonging to 10 species, using lactophenol cotton blue staining. Aborted pollen grains were found to be significantly smaller than normal ones. The results revealed differences in the percentage of normal grains among different species and tribes studied: Atripliceae (56.1 ± 27.1%), Salicornieae (80.36 ± 16.52%), Suaedeae (54.7 ± 31.2%) and Salsoleae (32.5 ± 25.7%). In some species there were significant differences among the populations studied, but in species of Saliconieae we found no differences either between different positions in the dicasia or in the anther. In the tribes Suaedeae and Salsoleae, we postulate the existence of a system that maintains different levels of partial male sterility among individuals in the populations, which would reduce the autogamous fruit set rate and favor the cross-pollination rates of sterile male individuals. We base this on high intrapopulation variability at those levels, on the constancy with which they are presented in the different populations studied, and on the lack of interannual differences.
The main objective of this study is to establish the level of pollen abortion prior to its releas... more The main objective of this study is to establish the level of pollen abortion prior to its release from the anther in species of Chenopodiaceae in marsh habitats and to compare this level among the taxons, locations and positions of the flowers in the dichasium and the relative positions of the anthers. We established the level of nonfunctional pollen formation in 39 samples belonging to 10 species, using lactophenol cotton blue staining. Aborted pollen grains were found to be significantly smaller than normal ones. The results revealed differences in the percentage of normal grains among different species and tribes studied: Atripliceae (56.1 ± 27.1%), Salicornieae (80.36 ± 16.52%), Suaedeae (54.7 ± 31.2%) and Salsoleae (32.5 ± 25.7%). In some species there were significant differences among the populations studied, but in species of Saliconieae we found no differences either between different positions in the dicasia or in the anther. In the tribes Suaedeae and Salsoleae, we postulate the existence of a system that maintains different levels of partial male sterility among individuals in the populations, which would reduce the autogamous fruit set rate and favor the cross-pollination rates of sterile male individuals. We base this on high intrapopulation variability at those levels, on the constancy with which they are presented in the different populations studied, and on the lack of interannual differences.
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
High dense bulk specimens of 0.55% C steel with ferritic grain sizes within the nanocrystalline a... more High dense bulk specimens of 0.55% C steel with ferritic grain sizes within the nanocrystalline and ultrafine regimes have been produced from ball-milled iron powder through the warm consolidation process. The microstructure, the mechanical properties and the strain rate sensitivity parameter (m) were investigated for the different grain sizes obtained. A constant decrease of m was found as the grain size decreases within the ultrafine regime. In the nanocrystalline regime, on the contrary, as the grain size decreases a slight increase of m was observed.
The strain rate sensitivity of three steels with carbon contents ranging from 0.05 to 0.55 wt.% h... more The strain rate sensitivity of three steels with carbon contents ranging from 0.05 to 0.55 wt.% has been determined by nanoindentation and compression tests in the nanocrystalline and ultrafine-grained ranges. Samples were obtained by warm consolidation from milled powders. In the nanocrystalline range the steel with higher carbon content was found to be slightly rate sensitive, which means that the presence of carbon involves a change in the deformation mechanism of body-centered cubic iron, resulting in grain boundaries contributing to the plasticity.
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Papers by Jaime Cabrera