248 research outputs found

    Phase profile analysis of transparent objects through the use of a two windows interferometer based on a one beam splitter configuration

    Get PDF
    AbstractIn this research we implemented a two windows interferometer based on polarization phase shifting and grating interferometry techniques in order to retrieve the phase data profile of the object in a single capture. The optical configuration has two optical beams with circular polarization in opposite directions, and it is coupled with a 4-f system. An amplitude grid is used as a filter which is placed at the Fourier plane to obtain replicas of each beam which can properly interfere, depending on the separation between beams. The interferometer presents the capability of changing the beam separation in order to make different orders interfere properly. The interference patterns produced can be separately modulated through the operation of linear polarizer's placed on each interference replica. In order to present the capabilities of the system we will select four interferograms result of contiguous orders interference

    Influencia de la microestructura en las propiedades mecánicas de alta temperatura de los Eutécticos Al2O3/Y3Al5O12 crecidos por solidificación direccional

    Get PDF
    En este trabajo se ha realizado un estudio del sistema eutéctico Al2O3/Y3Al5O12 crecido a distintas velocidades mediante solidificación direccional de zona flotante por calentamiento con láser. El análisis microestructural se ha realizado mediante Microscopía Electrónica de Barrido (MEB) y de Transmisión (MET), tanto en muestras tras el procesado con láser como en muestras sometidas a los distintos tratamientos termo-mecánicos. El estudio de las propiedades mecánicas se ha llevado a cabo mediante ensayos a velocidad de deformación constante y ensayos de fluencia -a carga de compresión constante- para diversos valores de tensión y de temperatura en atmósfera de aire. De los resultados obtenidos se deduce que la resistencia está íntimamente asociada a la microestructura de las muestras, la cual depende de la velocidad de solidificación. La presencia de dislocaciones es clara a altas velocidades de deformación, observándose los mecanismos activos de deformación típicos de la alúmina monocristalinas, como son la formación de bucles de dislocaciones para evitar obstáculos. Los valores de los exponentes de tensión y la energía de activación sugieren un comportamiento difusional para bajas velocidades de deformación, a las que no se observan dislocaciones.The Al2O3/Y3Al5O12 eutectic system melt grown by laser heating float zone in a range of pull rates has been studied. The microstructural analysis has been made by Scaning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) in as-fabricated and tested samples. The mechanical properties have been studied by compression tests at constant crosshead speed and compression creep for a range of stresses and temperatures in air. It has been determined that the resistance is intimately associated to processing. The presence of dislocations is clear after plastic deformation at high strain rates, being active the typical deformation mechanisms of alumina single crystals, like dislocation loop formation to avoid obstacles. The values of the stress exponents and the activation energy suggest a diffusional control for plastic deformation at low strain rates, where dislocations are not observed

    Experiencias interdisciplinarias en alimentación y daños a la salud en las fronteras sur y norte de México

    Get PDF
    Los problemas de salud y alimentación en diferentes contextos como las fronteras sur y norte de México exige de trabajo interdisciplinar, con lenguajes y bases comunes para los grupos académicos. El objetivo de esta ponencia es reflexionar sobre la experiencia del grupo Seminario de “Alimentación y Daños a la Salud” (ADAS), el cual busca consolidar una propuesta de colaboración interinstitucional para el abordaje interdisciplinario de los problemas de salud relacionados con la alimentación y vulnerabilidad social en la frontera sur y norte de México.Facultad de Humanidades y Ciencias de la Educació

    Experiencias interdisciplinarias en alimentación y daños a la salud en las fronteras sur y norte de México

    Get PDF
    Los problemas de salud y alimentación en diferentes contextos como las fronteras sur y norte de México exige de trabajo interdisciplinar, con lenguajes y bases comunes para los grupos académicos. El objetivo de esta ponencia es reflexionar sobre la experiencia del grupo Seminario de “Alimentación y Daños a la Salud” (ADAS), el cual busca consolidar una propuesta de colaboración interinstitucional para el abordaje interdisciplinario de los problemas de salud relacionados con la alimentación y vulnerabilidad social en la frontera sur y norte de México.Facultad de Humanidades y Ciencias de la Educació

    Sensory perspectives of the consumption of chips-type snacks made from black bean (Phaseolus vulgaris L) and peanut (Arachis hypogaea Linn) flours by university students in the Toluca Valley

    Get PDF
    Objective: The objective of this study is to evaluate the sensory perspectives of chips-type snacks made from black bean dry (Phaseolus vulgaris L) and peanut (Arachis hypogaea Linn) flours in a university population. Design/methodology/approach: Two formulations were realized from peanut and black bean previously toasted and milled: 1) (PF) 50% peanut flour, 12.5% rice flour and 12.5 % cornstarch; 2) (BbF) 50% black bean flour, 12.5% wheat flour and 12.5% cornstarch. Each mixture of flours was extruded and fried until obtained chips-type snacks. A statistical-descriptive study was carried out from the observation of the eating habits of university students in the State of Mexico. On other hand, an affective test was tested to evaluate the acceptance of chips-type snacks made with PF and BbF in the categories of odor, taste, hardness, and easy to break. Findings/conclusion: According to the questionnaire, the female gender has higher snack consumption than the male population. On another hand, potato chips are in third place as the most consumed snacks for women they preferred to consume them in their houses. Peanut and chickpea flour are the most preferred by the female population. There was no significant difference (p˃0.05) between the snacks prepared with PF and BbF, but 60% of the consumer accepted both snacks. It is concluded that the chips-type snacks made with different formulations could be a healthy alternative for the students, also it kind of products have good acceptability. Finally knowing the sensory perspectives could provide important information for developing healthier and easier-to-eat snacks. Limitations on study/implications: More studies about the characterization of the chips-type snacks are required, also a mix of both legumes could be realized

    Evaluation of the Expression of Genes Associated with Inflammation and Apoptosis in Androgenetic Alopecia by Targeted RNA-Seq

    Get PDF
    Abstract Androgenetic alopecia (AGA) or male pattern baldness is the most common form of hair loss in humans. Despite being a very frequent dermatological entity, molecular pathophysiology remains unclear. Several authors relate the presentation of AGA with a premature apoptotic process during the anagen phase and with an inflammatory microenvironment in the hair follicle. We evaluated a panel of 30 genes associated with inflammation and apoptosis in 5 AGA patients by targeted RNA-Seq. WNT7A gene was highly expressed in patients in stages 3V to 5 on the Hamilton-Norwood scale compared to patients with 5A stage. CASP7 and TNF genes were overexpressed in stages 3V and 4 compared to stages 5 and 5A. Overexpression of these genes detected only at early stages of AGA proves the role of WNT pathway, apoptosis, and inflammation in the development of this disorder

    Tipping point detection and early warnings in climate, ecological, and human systems

    Get PDF
    Tipping points characterize the situation when a system experiences abrupt, rapid, and sometimes irreversible changes in response to only a gradual change in environmental conditions. Given that such events are in most cases undesirable, numerous approaches have been proposed to identify if a system is approaching a tipping point. Such approaches have been termed early warning signals and represent a set of methods for identifying statistical changes in the underlying behaviour of a system across time or space that would be indicative of an approaching tipping point. Although the idea of early warnings for a class of tipping points is not new, in the last 2 decades, the topic has generated an enormous amount of interest, mainly theoretical. At the same time, the unprecedented amount of data originating from remote sensing systems, field measurements, surveys, and simulated data, coupled with innovative models and cutting-edge computing, has made possible the development of a multitude of tools and approaches for detecting tipping points in a variety of scientific fields. However, we miss a complete picture of where, how, and which early warnings have been used so far in real-world case studies. Here we review the literature of the last 20 years to show how the use of these indicators has spread from ecology and climate to many other disciplines. We document what metrics have been used; their success; and the field, system, and tipping points involved. We find that, despite acknowledged limitations and challenges, in the majority of the case studies we reviewed, the performance of most early warnings was positive in detecting tipping points. Overall, the generality of the approaches employed – the fact that most early warnings can in theory be observed in many dynamical systems – explains the continuous multitude and diversification in their application across scientific domains.Chris A. Boulton, Joshua E. Buxton, and David I. Armstrong McKay were supported by the Bezos Earth Fund via the Global Tipping Points Report project. Carlos López Martínez was supported by INTERACT project PID2020-114623RB-C32 funded by MCIN/AEI/10.13039/501100011033.Peer ReviewedPostprint (published version

    Tipping point detection and early warnings in climate, ecological, and human systems

    Get PDF
    Tipping points characterize the situation when a system experiences abrupt, rapid, and sometimes irreversible changes in response to only a gradual change in environmental conditions. Given that such events are in most cases undesirable, numerous approaches have been proposed to identify if a system is approaching a tipping point. Such approaches have been termed early warning signals and represent a set of methods for identifying statistical changes in the underlying behaviour of a system across time or space that would be indicative of an approaching tipping point. Although the idea of early warnings for a class of tipping points is not new, in the last 2 decades, the topic has generated an enormous amount of interest, mainly theoretical. At the same time, the unprecedented amount of data originating from remote sensing systems, field measurements, surveys, and simulated data, coupled with innovative models and cutting-edge computing, has made possible the development of a multitude of tools and approaches for detecting tipping points in a variety of scientific fields. However, we miss a complete picture of where, how, and which early warnings have been used so far in real-world case studies. Here we review the literature of the last 20 years to show how the use of these indicators has spread from ecology and climate to many other disciplines. We document what metrics have been used; their success; and the field, system, and tipping points involved. We find that, despite acknowledged limitations and challenges, in the majority of the case studies we reviewed, the performance of most early warnings was positive in detecting tipping points. Overall, the generality of the approaches employed – the fact that most early warnings can in theory be observed in many dynamical systems – explains the continuous multitude and diversification in their application across scientific domains.</p

    Obesity Indexes and Total Mortality among Elderly Subjects at High Cardiovascular Risk: The PREDIMED Study

    Get PDF
    BackgroundDifferent indexes of regional adiposity have been proposed for identifying persons at higher risk of death. Studies specifically assessing these indexes in large cohorts are scarce. It would also be interesting to know whether a dietary intervention may counterbalance the adverse effects of adiposity on mortality.MethodsWe assessed the association of four different anthropometric indexes (waist-to-height ratio (WHtR), waist circumference (WC), body mass index (BMI) and height) with all-cause mortality in 7447 participants at high cardiovascular risk from the PREDIMED trial. Forty three percent of them were men (55 to 80 years) and 57% were women (60 to 80 years). All of them were initially free of cardiovascular disease. The recruitment took place in 11 recruiting centers between 2003 and 2009.ResultsAfter adjusting for age, sex, smoking, diabetes, hypertension, intervention group, family history of coronary heart disease, and leisure-time physical activity, WC and WHtR were found to be directly associated with a higher mortality after 4.8 years median follow-up. The multivariable-adjusted HRs for mortality of WHtR (cut-off points: 0.60, 0.65, 0.70) were 1.02 (0.78–1.34), 1.30 (0.97–1.75) and 1.55 (1.06–2.26). When we used WC (cut-off points: 100, 105 and 110 cm), the multivariable adjusted Hazard Ratios (HRs) for mortality were 1.18 (0.88–1.59), 1.02 (0.74–1.41) and 1.57 (1.19–2.08). In all analyses, BMI exhibited weaker associations with mortality than WC or WHtR. The direct association between WHtR and overall mortality was consistent within each of the three intervention arms of the trial.ConclusionsOur study adds further support to a stronger association of abdominal obesity than BMI with total mortality among elderly subjects at high risk of cardiovascular disease. We did not find evidence to support that the PREDIMED intervention was able to counterbalance the harmful effects of increased adiposity on total mortality.Trial RegistrationControlled-Trials.com ISRCTN3573963

    Dietary intake of polychlorinated dibenzo-p-dioxins and furans, adiposity and obesity status

    Full text link
    Introduction: The principal source of exposure to Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) in humans comes from food intake. PCDD/Fs, are a family of potential endocrine disruptors and have been associated with different chronic diseases such as diabetes and hypertension. However, studies assessing the relationship between dietary exposure to PCDD/Fs and adiposity or obesity status in a middle-aged population are limited. Objective: To assess cross-sectionally and longitudinally the associations between estimated dietary intake (DI) of PCDD/Fs and body mass index (BMI), waist circumference, and the prevalence/incidence of obesity and abdominal obesity in a middle-aged population. Methods: In 5899 participants aged 55-75 years (48% women) living with overweight/obesity from the PREDIMED-plus cohort, PCDD/Fs DI was estimated using a 143-item validated food-frequency questionnaire, and the levels of food PCDD/F expressed as Toxic Equivalents (TEQ). Consequently, cross-sectional and prospective associations between baseline PCDD/Fs DI (in pgTEQ/week) and adiposity or obesity status were assessed at baseline and after 1-year follow-up using multivariable cox, logistic or linear regression models. Results: Compared to participants in the first PCDD/F DI tertile, those in the highest tertile presented a higher BMI (β-coefficient [confidence interval]) (0.43kg/m2 [0.22; 0.64]; P-trend <0.001), a higher waist circumference (1.11 cm [0.55; 1.66]; P-trend <0.001), and a higher prevalence of obesity and abdominal obesity (1.05 [1.01; 1.09] and 1.02 [1.00; 1.03]; P-trend = 0.09 and 0.027, respectively). In the prospective analysis, participants in the top PCDD/F DI baseline tertile showed an increase in waist circumference compared with those in the first tertile after 1-year of follow-up (β-coefficient 0.37 cm [0.06; 0.70]; P-trend = 0.015). Conclusion: Higher DI of PCDD/Fs was positively associated with adiposity parameters and obesity status at baseline and with changes in waist circumference after 1-year of follow-up in subjects living with overweight/obesity. Further large prospective studies using a different population with longer follow-up periods are warranted in the future to strengthen our results. Keywords: Abdominal obesity; Adiposity; Endocrine disrupting chemicals; Obesity; Polychlorinated dibenzo-p-furans (PCDD/F)
    corecore