139 research outputs found
Introductory Chapter: Ceramic Materials - Synthesis, Characterization, Applications and Recycling
Clustering classification of cyclists according to the acute fatigue outcomes produced by an ultra-endurance event
This study aimed to analyze the differences between clusters obtained by the acute effect of fatigue after an ultra-endurance event in the internal and external load of cyclists. 26 volunteers participated in the study, and they were divided into the experimental group (N = 18; height: 177 ± 8 cm; body mass: 78.6 ± 10.3 kg) and the control group (N = 8; height: 176 ± 10 cm; body mass: 78.0 ± 15.7 kg). The experimental group completed a 12 h non-stop cycling event. Jump height, lactate, plasma antioxidant capacity, pain perception and fatigue perception were measured before and after the event. Cyclists of the experimental group were classified considering their training characteristics (recreational vs. competitive) and by conducting a non-supervised K-means clustering. The differentiation of cyclists according to training characteristics resulted in a lower distance covered by recreational than competitive cyclists (279.4 ± 39.7 km vs. 371.0 ± 71.7 km; ES ≥ 0.8; p 0.05). The clustering analysis provided two clusters. Cluster 2 suffered a greater jump height reduction (-3.3 ± 1.6 vs. 1.2 ± 0.8; ES ≥ 0.8; p < 0.001) and increased pain and fatigue perception (ES ≥ 0.5; p < 0.05) after the race than Cluster 1. In conclusion, counter-movement jump can differentiate the fatigue produced by a cycling ultra-endurance event and therefore, this non-invasive technique is useful in fatigue monitoring and recovery planification
Application of Photon Strength Functions to (n,g ) measurements with the n_TOF TAC
The neutron capture cross section measurements at the CERN n_TOF facility are performed using
a new detection system, the segmented Total Absorption Calorimeter (TAC). All measurements
are performed in reference to the well known Au σ(n,γ).
The accuracy of the measurements depends on the accuracy of the TAC detection efficiency,
which is calculated by means of Monte Carlo simulations. In this MC simulation photon strength
functions and level densities play a major role as ingredients used for the generation of primary
events, that is the electromagnetic cascades following the (n,γ) process. We have calculated the
TAC detection efficiency for the case of Au (n,γ) by adjusting the photon strength functions
of Au so that the simulation reproduces the experimental data. Both the MC method and the
uncertainty of the results are discussed
Familial Combined Hyperlipidemia (FCH) Patients with High Triglyceride Levels Present with Worse Lipoprotein Function Than FCH Patients with Isolated Hypercholesterolemia
Lipoprotein characteristics were analyzed in familial combined hyperlipidemia (FCH) patients before and after statin treatment. Twenty-six FCH patients were classified according to the presence (HTG group, n = 13) or absence (normotriglyceridemic (NTG) group, n = 13) of hypertriglyceridemia. Fifteen healthy subjects comprised the control group. Lipid profile, inflammation markers, and qualitative characteristics of lipoproteins were assessed. Both groups of FCH subjects showed high levels of plasma C-reactive protein (CRP), lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and apolipoprotein J. Statins reverted the increased levels of Lp-PLA2 and CRP. Lipoprotein composition alterations detected in FCH subjects were much more frequent in the HTG group, leading to dysfunctional low-density lipoproteins (LDL) and high-density lipoproteins (HDL). In the HTG group, LDL was smaller, more susceptible to oxidation, and contained more electronegative LDL (LDL(-)) compared to the NTG and control groups. Regarding HDL, the HTG group had less Lp-PLA2 activity than the NTG and control groups. HDL from both FCH groups was less anti-inflammatory than HDL from the control group. Statins increased LDL size, decreased LDL(-), and lowered Lp-PLA2 in HDL from HTG. In summary, pro-atherogenic alterations were more frequent and severe in the HTG group. Statins improved some alterations, but many remained unchanged in HTG
La importancia de antecedentes y ejemplos en la comprensión efectiva de conceptos ecológicos por alumnos universitarios
La importancia de tener conceptos claros en Ecología resulta esencial en todas las titulaciones universitarias cuyos profesionales participan en la gestión medioambiental. En la UA diferentes grados incluyen estos conceptos entre sus objetivos formativos. En la presente contribución se recopila la opinión de grupos de alumnos de los grados en Biología, Química, Geología, y Sociología. Se valoran los antecedentes formativos en el ámbito ecológico de los alumnos encuestados, así como la opinión sobre diferentes problemas ambientales de ámbito local, para optimizar la eficacia del proceso enseñanza-aprendizaje. Esta encuesta se cumplimentó, vía Internet, por grupos de alumnos pertenecientes a las titulaciones mencionadas. En ella se analiza la perspectiva de los encuestados tanto sobre conceptos de ecología, como de las aplicaciones prácticas consideradas relevantes por ellos. La encuesta se subdivide en cuatro bloques referidos a : 1) Exploración de la motivación del alumno por las Ciencias del Medio Ambiente, 2) Actividades docentes que realizaron si cursaron Ciencias de la Tierra y del Medio Ambiente (CTMA) en secundaria, 3) Propuestas de nuevas actividades en la asignatura, 4) Conocimiento del entorno y sus problemas ambientales. Se valoran los resultados y diferencias que se detectan en su apreciación de los conceptos ecológicos. Se discuten los métodos a incorporar, en la práctica, en el diseño de las guías docentes de las respectivas asignaturas. Representa una ampliación de un análisis iniciado en el programa redes de 2012-13
Study of a Waste Kaolin as Raw Material for Mullite Ceramics and Mullite Refractories by Reaction Sintering
A deposit of raw kaolin, located in West Andalusia (Spain), was studied in this work using a representative sample. The methods of characterization were X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis by sieving and sedimentation, and thermal analysis. The ceramic properties were determined. A sample of commercial kaolin from Burela (Lugo, Spain), with applications in the ceramic industry, was used in some determinations for comparison purposes. The kaolin deposit has been produced by alteration of feldspar-rich rocks. This raw kaolin was applied as an additive in local manufactures of ceramics and refractories. However, there is not previous studies concerning its characteristics and firing properties. Thus, the meaning of this investigation was to conduct a scientific study on this subject and to evaluate the possibilities of application. The raw kaolin was washed for the beneficiation of the rock using water to increase the kaolinite content of the resultant material. The results indicated that the kaolinite content of the raw material was 20 wt % as determined by XRD, showing ~23 wt % of particles lower than 63 µm. The kaolinite content of the fraction lower than 63 µm was 50 wt %. Thus, an improvement of the kaolinite content of this raw kaolin was produced by wet separation. However, the kaolin was considered as a waste kaolin, with microcline, muscovite and quartz identified by XRD. Thermal analyses by Thermo-Dilatometry (TD), Differential Thermal Analysis (DTA) and Thermo-Gravimetry (TG) allowed observe kaolinite thermal decomposition, quartz phase transition and sintering effects. Pressed samples of this raw kaolin, the fraction lower than 63 µm obtained by water washing and the raw kaolin ground using a hammer mill were fired at several temperatures in the range 1000–1500 °C for 2 h. The ceramic properties of all these samples were determined and compared. The results showed the progressive linear firing shrinkage by sintering in these samples, with a maximum value of ~9% in the fraction lower than 63 µm. In general, water absorption capacity of the fired samples showed a decrease from ~18–20% at 1050 °C up to almost zero after firing at 1300 °C, followed by an increase of the experimental values. The open porosity was almost zero after firing at 1350 °C for 2 h and the bulk density reached a maximum value of 2.40 g/cm3 as observed in the ground raw kaolin sample. The XRD examination of fired samples indicated that they are composed by mullite, from kaolinite thermal decomposition, and quartz, present in the raw sample, as main crystalline phases besides a vitreous phase. Fully-densified or vitrified materials were obtained by firing at 1300–1350 °C for 2 h. In a second step of this research, it was examined the promising application of the previous study to increase the amount of mullite by incorporation of alumina (α-alumina) to this kaolin sample. Firing of mixtures, prepared using this kaolin and α-alumina under wet processing conditions, produced the increase of mullite in relative proportion by reaction sintering at temperatures higher than 1500 °C for 2 h. Consequently, a mullite refractory can be prepared using this kaolin. This processing of high-alumina refractories is favoured by a previous size separation, which increases the kaolinite content, or better a grinding treatment of the raw kaolin
CTYMA+2_Conexión y Coherencia disciplinar entre Ciencias de la Tierra y del Medio Ambiente y asignaturas afines de Ecología de la UA
La red CTYMA, desde su inicio, se dirigió a identificar y analizar los factores que condicionan el éxito en la formación ecológica a nivel universitario. Tener conceptos claros en Ecología resulta esencial en todas las titulaciones universitarias cuyos profesionales participan en la gestión medioambiental. Durante el curso 2013-14 priorizamos dos perspectivas: a) la de los alumnos universitarios de su etapa en secundaria, b) la de los profesores de secundaria sobre las limitaciones o condicionantes relevantes para la docencia de CTYMA. La presente contribución desarrolla más ampliamente el primer aspecto. Los alumnos encuestados cursan grados en Biología, Química, Geología, y Sociología. La encuesta cumplimentada, vía Internet, analiza sus respuestas sobre cuatro bloques: 1) Exploración de la motivación del alumno por las Ciencias del Medio Ambiente, 2) Actividades docentes que realizaron si cursaron Ciencias de la Tierra y del Medio Ambiente (CTYMA) , 3) Propuestas de nuevas actividades en dicha asignatura, 4) Conocimiento del entorno próximo y valoración de problemas ambientales de ámbito local. Se valoran y discuten las diferencias detectadas en su apreciación de los conceptos ecológicos. Se sugieren acciones a incorporar en las guías docentes universitarias afines. Representa una ampliación de un análisis iniciado en el programa redes de 2012-13
Characterizing diagnostic inertia in arterial hypertension with a gender perspective in primary care
Background and Objectives: Substantial evidence shows that diagnostic inertia leads to failure to achieve screening and diagnosis objectives for arterial hypertension (AHT). In addition, different studies suggest that the results may differ between men and women. This study aimed to evaluate the differences in diagnostic inertia in women and men attending public primary care centers, to identify potential gender biases in the clinical management of AHT. Study Design/Materials and methods: Cross-sectional descriptive and analytical estimates were obtained nested on an epidemiological ambispective cohort study of patients aged ≥30 years who attended public primary care centers in a Spanish region in the period 2008-2012, belonging to the ESCARVAL-RISK cohort. We applied a consistent operational definition of diagnostic inertia to a registry- reflected population group of 44,221 patients with diagnosed hypertension or meeting the criteria for diagnosis (51.2% women), with a mean age of 63.4 years (62.4 years in men and 64.4 years in women). Results: Of the total population, 95.5% had a diagnosis of hypertension registered in their electronic health record. Another 1,968 patients met the inclusion criteria for diagnostic inertia of hypertension, representing 4.5% of the total population (5% of men and 3.9% of women). The factors significantly associated with inertia were younger age, normal body mass index, elevated total cholesterol, coexistence of diabetes and dyslipidemia, and treatment with oral antidiabetic drugs. Lower inertia was associated with age over 50 years, higher body mass index, normal total cholesterol, no diabetes or dyslipidemia, and treatment with lipid-lowering, antiplatelet, and anticoagulant drugs. The only gender difference in the association of factors with diagnostic inertia was found in waist circumference. Conclusion: In the ESCARVAL-RISK study population presenting registered AHT or meeting the functional dia
Doctor Faustino Pérez Hernández: desarrollo con enfoque social en Cuba
Fundamento: El tema del desarrollo ha evolucionado desde la perspectiva cuantitativa a la cualitativa con un enfoque integral; estos enfoques en Cuba han estado presentes en el pensamiento económico y político. Es insuficientemente conocido el ideario y obra de Faustino Pérez Hernández, quien en el cumplimiento de funciones políticas y administrativas abordó aspectos sobre el desarrollo con proyección integradora.
Objetivo: Fundamentar que en el pensamiento y la obra del Dr. Faustino Pérez Hernández existe un enfoque social sobre el desarrollo en Cuba.
Desarrollo: Se fundamenta ese pensamiento y obra en distintos momentos: cuando elige la carrera de Medicina y fungió como miembro de la Comisión Médica del Partido Ortodoxo, durante sus funciones como Comisionado General de la Administración Civil de los Territorios Liberados, siendo Ministro de Recuperación de Bienes Malversados; como Presidente del Instituto Nacional de Recursos Hidráulicos, como Primer Secretario del Partido Comunista de Cuba de la Región de Sancti Spíritus y desde su condición de Jefe del Plan Integral de la Ciénaga de Zapata.
Conclusiones: En el pensamiento y la obra del Dr. Faustino Pérez Hernández existe un enfoque social sobre el desarrollo en Cuba con una proyección integral, que incluye la solución de los problemas relacionados con la salud del pueblo, constatable en su diverso accionar en el cumplimiento de importantes misiones, siguiendo un camino de ascendente maduración en dos planos o niveles: nacional y local
Factores clínicos y demográficos predictores de éxito del misoprostol en el tratamiento médico del aborto espontáneo
Objetivos: Determinar posibles predictores de éxito del misoprostol en el tratamiento del aborto espontáneo del primer trimestre. Método: Estudio observacional descriptivo y prospectivo, realizado entre febrero de 2009 y febrero de 2010. Inclusión consecutiva de 248 mujeres con diagnostico ecográfico de aborto espontáneo del primer trimestre con tratamiento médico o quirúrgico, siendo las pacientes las que eligieron la opción terapéutica de acuerdo a los criterios de inclusión para el manejo con misoprostol. En el grupo tratamiento médico se aplicó 800 mcg de misoprostol vaginal/24horas/2 dosis, considerándose como criterio de éxito un endometrio homogéneo con grosor <15 mm en la ecografía realizada al 8° día del tratamiento. Resultados: Influyen en la tasa de éxito del misoprostol la edad de las pacientes (mejor resultado cuanto más joven, p=0,025), número de embarazos (responden mejor las primigestas, p=0,024), existencia o no de abortos (p=0,05) o legrados previos (p=0,028) (la tasa de éxito del misoprostol es mayor en las mujeres que no tienen ningún aborto o legrado previo), y tipo de sangrado vaginal que aparece como efecto secundario del misoprostol (mejorando el pronóstico cuando dicho sangrado es igual o mayor que menstruación, p=0,041). Conclusiones: Hubo predictores de éxito del misoprostol que pueden orientar el manejo, sabiendo que hubo mejor resultado en pacientes jóvenes, primigestas, sin abortos ni legrados previos y con un sangrado vaginal igual o mayor que menstruación
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