22 research outputs found

    Reflexiones sobre el método en economía desde la teoría del consumo

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    El presente documento reflexiona sobre el uso del método inductivo y deductivo en el análisis del consumo que realizaron dos autores del siglo XIX: Thorstein Veblen   y   Carl   Menger,   respectivamente.   Se   plantea   que   en   el   debate metodológico del siglo XIX cobró poca relevancia el ejercicio de constatación empírica  de  planteamientos  teóricos  a  raíz  de  la  conciencia  del  carácter limitado de la teoría. Sobre esta base, las teorías del consumo se construyeron a partir  de  propuestas  analíticas  propias  del  razonamiento  deductivo  sobre  tres premisas apriorísticas básicas: individuo asocial, insaciabilidad y orientación a los   bienes. Sin embargo, este programa de investigación se ha degenerado en el sentido de Lakatos por los cuestionamientos de Veblen, Galbraith, Keynes y Akerman   entre  otros.   De  ahí  que  para  favorecer   la  construcción  de  un programa de investigación progresivo en términos metodológicos y empíricos sea necesaria la integración de los métodos deductivo e inductivo en economía y el avance hacia presupuestos teóricos consistentes con realidades históricas cambiantes

    Tool steel selection for cold forming of high strength steels based on the stress distribution in tools

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    The excellent combination of high mechanical strength, high elongation and strain hardening of Advanced High Strength Steels (AHSS) has allowed their increasing use in the automobile industry to reduce vehicle weight and thereby fuel consumption while improving crash performance. However, the implementation of such high strength materials has generated difficulties related to wear acceleration and premature failure of forming tools. High loading during cold forming of AHSS increases to a great extent the tool requirements in terms of toughness and hardness properties. The main alternative to overcome these difficulties involves an optimized selection tool material through a proper evaluation of the stress state in the tools themselves. In this work, stress states on tooling during cold forming of AHSS have been evaluated by means of finite element simulation. The calculated results allow selecting the most suitable tool steel in terms of microstructure and mechanical properties.Postprint (published version

    Actualidad y prospectiva de la investigación científica en el Centro Universitario Amecameca de la Universidad Autónoma del Estado de México

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    Con responsabilidad, se organizó un programa cuya finalidad fuera publicitar con transparencia dichos avances, a través de un esfuerzo de rendición de cuentas a la comunidad inmediata, la universitaria, y a la comunidad abierta, la sociedad que la principal referencia para tal efecto. El programa se concretiza a través del presente libro, conformado con una inspiración de investigación multidisciplinaria; sin embargo, para llegar a tal fin, el reto es realizar el proceso de búsqueda y generación de conocimiento transitando hacia la colaboración de los cuerpos académicos, que puedan construir nuevos conocimientos fortalecidos por la convergencia de diferentes campos del saber. En consecuencia, la primera etapa de esta estrategia es la publicidad de los trabajos investigativos ejercidos, para hacer un balance al día, pero también proyectar el futuro de cada campo y área del conocimiento. La organización explicativa está organizada por tres bloques representativos del quehacer en la generación de conocimiento del Centro Universitario, un primer bloque centra el interés en las humanidades, educación y sustentabilidad; el segundo bloque lo integra la reflexión científica sobre la construcción democrática, derechos humanos y equidad de género; en el tercer segmento se destina a la seguridad alimentaria, salud pública y sistemas agropecuarios. La actualidad de la investigación eleva la producción lograda y lo que en el momento se encuentra en construcción y los alcances que produce para la docencia, la investigación misma, y para la sociedad en general. La prospectiva es un área que todos los capítulos desarrollan con el propósito de delinear los alcances innovadores por andar en teoría, metodología e incluso en los saberes mismo

    Spatiotemporal Characteristics of the Largest HIV-1 CRF02_AG Outbreak in Spain: Evidence for Onward Transmissions

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    Background and Aim: The circulating recombinant form 02_AG (CRF02_AG) is the predominant clade among the human immunodeficiency virus type-1 (HIV-1) non-Bs with a prevalence of 5.97% (95% Confidence Interval-CI: 5.41–6.57%) across Spain. Our aim was to estimate the levels of regional clustering for CRF02_AG and the spatiotemporal characteristics of the largest CRF02_AG subepidemic in Spain.Methods: We studied 396 CRF02_AG sequences obtained from HIV-1 diagnosed patients during 2000–2014 from 10 autonomous communities of Spain. Phylogenetic analysis was performed on the 391 CRF02_AG sequences along with all globally sampled CRF02_AG sequences (N = 3,302) as references. Phylodynamic and phylogeographic analysis was performed to the largest CRF02_AG monophyletic cluster by a Bayesian method in BEAST v1.8.0 and by reconstructing ancestral states using the criterion of parsimony in Mesquite v3.4, respectively.Results: The HIV-1 CRF02_AG prevalence differed across Spanish autonomous communities we sampled from (p < 0.001). Phylogenetic analysis revealed that 52.7% of the CRF02_AG sequences formed 56 monophyletic clusters, with a range of 2–79 sequences. The CRF02_AG regional dispersal differed across Spain (p = 0.003), as suggested by monophyletic clustering. For the largest monophyletic cluster (subepidemic) (N = 79), 49.4% of the clustered sequences originated from Madrid, while most sequences (51.9%) had been obtained from men having sex with men (MSM). Molecular clock analysis suggested that the origin (tMRCA) of the CRF02_AG subepidemic was in 2002 (median estimate; 95% Highest Posterior Density-HPD interval: 1999–2004). Additionally, we found significant clustering within the CRF02_AG subepidemic according to the ethnic origin.Conclusion: CRF02_AG has been introduced as a result of multiple introductions in Spain, following regional dispersal in several cases. We showed that CRF02_AG transmissions were mostly due to regional dispersal in Spain. The hot-spot for the largest CRF02_AG regional subepidemic in Spain was in Madrid associated with MSM transmission risk group. The existence of subepidemics suggest that several spillovers occurred from Madrid to other areas. CRF02_AG sequences from Hispanics were clustered in a separate subclade suggesting no linkage between the local and Hispanic subepidemics

    Elementos de matemáticas para economía

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    El presente texto está dirigido particularmente a los estudiantes de las especializaciones en Evalución de proyectos, Mercado de capitales y Finanzas, de la Facultad de Economía de la Universidad del Rosario. Redesarrolla para estudiar funciones de varias variables, funciones homogéneas, curvas de nivel, derivadas parciales, elasticidad parcial, optimización con y sin restricción, integrales como cálculo de áreas y antiderivadas y, por último, introducción al álgebra de matrices

    Tool steel selection for cold forming of high strength steels based on the stress distribution in tools

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    The excellent combination of high mechanical strength, high elongation and strain hardening of Advanced High Strength Steels (AHSS) has allowed their increasing use in the automobile industry to reduce vehicle weight and thereby fuel consumption while improving crash performance. However, the implementation of such high strength materials has generated difficulties related to wear acceleration and premature failure of forming tools. High loading during cold forming of AHSS increases to a great extent the tool requirements in terms of toughness and hardness properties. The main alternative to overcome these difficulties involves an optimized selection tool material through a proper evaluation of the stress state in the tools themselves. In this work, stress states on tooling during cold forming of AHSS have been evaluated by means of finite element simulation. The calculated results allow selecting the most suitable tool steel in terms of microstructure and mechanical properties

    Maculopapular eruptions associated to COVID-19: A subanalysis of the COVID-Piel study.

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    A previous study has defined the maculopapular subtype of manifestations of COVID-19. The objective of our study was to describe and classify maculopapular eruptions associated with COVI-19. We carried out a subanalysis of the maculopapular cases found in the previous cross-sectional study. Using a consensus, we defined seven clinical patterns. We described patient demographics, the therapy received by the patient and the characteristics of each pattern. Consensus lead to the description of seven major maculopapular patterns: morbilliform (45.5%), other maculopapular (20.0%), purpuric (14.2%), erythema multiforme-like (9.7%), pytiriasis rosea-like (5.7%), erythema elevatum diutinum-like (2.3%), and perifollicular (2.3%). In most cases, maculopapular eruptions were coincident (61.9%) or subsequent (34.1%) to the onset of other COVID-19 manifestations. The most frequent were cough (76%), dyspnea (72%), fever (88%), and astenia (62%). Hospital admission due to pneumonia was frequent (61%). Drug intake was frequent (78%). Laboratory alterations associated with maculo-papular eruptions were high C-reactive protein, high D-Dimer, lymphopenia, high ferritin, high LDH, and high IL-6. The main limitation of our study was the impossibility to define the cause-effect relationship of each pattern. In conclusion, we provide a description of the cutaneous maculopapular manifestations associated with COVID-19. The cutaneous manifestations of COVID-19 are wide-ranging and can mimic other dermatoses

    How do women living with HIV experience menopause? Menopausal symptoms, anxiety and depression according to reproductive age in a multicenter cohort

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    CatedresBackground: To estimate the prevalence and severity of menopausal symptoms and anxiety/depression and to assess the differences according to menopausal status among women living with HIV aged 45-60 years from the cohort of Spanish HIV/AIDS Research Network (CoRIS). Methods: Women were interviewed by phone between September 2017 and December 2018 to determine whether they had experienced menopausal symptoms and anxiety/depression. The Menopause Rating Scale was used to evaluate the prevalence and severity of symptoms related to menopause in three subscales: somatic, psychologic and urogenital; and the 4-item Patient Health Questionnaire was used for anxiety/depression. Logistic regression models were used to estimate odds ratios (ORs) of association between menopausal status, and other potential risk factors, the presence and severity of somatic, psychological and urogenital symptoms and of anxiety/depression. Results: Of 251 women included, 137 (54.6%) were post-, 70 (27.9%) peri- and 44 (17.5%) pre-menopausal, respectively. Median age of onset menopause was 48 years (IQR 45-50). The proportions of pre-, peri- and post-menopausal women who had experienced any menopausal symptoms were 45.5%, 60.0% and 66.4%, respectively. Both peri- and post-menopause were associated with a higher likelihood of having somatic symptoms (aOR 3.01; 95% CI 1.38-6.55 and 2.63; 1.44-4.81, respectively), while post-menopause increased the likelihood of having psychological (2.16; 1.13-4.14) and urogenital symptoms (2.54; 1.42-4.85). By other hand, post-menopausal women had a statistically significant five-fold increase in the likelihood of presenting severe urogenital symptoms than pre-menopausal women (4.90; 1.74-13.84). No significant differences by menopausal status were found for anxiety/depression. Joint/muscle problems, exhaustion and sleeping disorders were the most commonly reported symptoms among all women. Differences in the prevalences of vaginal dryness (p = 0.002), joint/muscle complaints (p = 0.032), and sweating/flush (p = 0.032) were found among the three groups. Conclusions: Women living with HIV experienced a wide variety of menopausal symptoms, some of them initiated before women had any menstrual irregularity. We found a higher likelihood of somatic symptoms in peri- and post-menopausal women, while a higher likelihood of psychological and urogenital symptoms was found in post-menopausal women. Most somatic symptoms were of low or moderate severity, probably due to the good clinical and immunological situation of these women
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