225 research outputs found

    El intelecto agente en Pietro Pomponazzi: un análisis de su presencia en el Tractatus de immortalitate animae y en la Apologia

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    El noûs poie-tikós de Aristóteles ha sido objeto de innumerables estudios y debates a lo largo de la historia de la filosofía. Este artículo trata sobre la visión que de él tiene el aristotélico renacentista P. Pomponazzi, célebre, entre otras cosas, por suscitar una agria polémica con su tesis de que la razón natural no ofrece argumentos que puedan sostener la inmortalidad del alma. Esta tesis tiene que dar respuesta, sin embargo, a aquellos textos aristotélicos que hablan de la inmaterialidad e inmortalidad del intelecto. El autor estudia esta respuesta de Pomponazzi en el contexto de los elementos más importantes de su psicología.The noûs poie-tikós of Aristotle has been the subject of countless studies and debates throughout the history of philosophy. This paper deals with the treatment of Pietro Pomponazzi, an Aristotelian philosopher who is famous for the bitter controversy caused by his claim that natural reason cannot offer arguments in favour of the immortality of the soul. Pomponazzi has to respond to Aristotelian texts that attribute immateriality and immortality to the intellect. The author analyses the way in which Pomponazzi interprets these texts in the Tractatus de immortalitate animae and the Apologia and links this interpretation to the most characteristic elements of his psychology

    Mechanical modeling of collective cell migration: An agent-based and continuum material approach

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    We develop a novel modeling approach that combines a discrete agent-based model and a continuum material model to simulate collective cell migration in epithelial layers. In this approach, cells are represented as particles located at their geometrical center, but also as a polygonal body derived from the Voronoi diagram. Furthermore, we model the tissue as a continuum medium with different spatial domains that represent cell and substrate materials. In fact, the mechanical behavior of each domain is affected by the presence of cells from the discrete model. Moreover, we solve this mechanical problem using the finite element method (FEM). The forces generated by cells are projected to the FE mesh, that is created dynamically during the simulation from the discrete cell representation. After the FE resolution, we use the mesh displacements to determine the new cell positions in the agent-based model. Finally, to demonstrate the potential of this approach to model epithelial tissue mechanics, we simulate two well-studied cases of collective cell migration: durotaxis and gap closure. We use the experimental data from the literature to validate our numerical results. Therefore, the modeling strategy here presented offers a new perspective for a deeper understanding of tissue mechanics that emerge from cell dynamics in epithelial layers

    Novel mutations in BMPR2, ACVRL1 and KCNA5 genes and hemodynamic parameters in patients with pulmonary arterial hypertension.

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    Background: Pulmonary arterial hypertension (PAH) is a rare and progressive vascular disorder characterized by increased pulmonary vascular resistance and right heart failure. The aim of this study was to analyze the Bone Morphogenetic Protein Receptor 2 (BMPR2), Activin A type II receptor like kinase 1 (ALK1/ACVRL1) and potassium voltage-gated channel, shakerrelated subfamily, member 5 (KCNA5) genes in patients with idiopathic and associated PAH. Correlation among pathogenic mutations and clinical and functional parameters was further analyzed. Methods and results: Forty one patients and fifty controls were included in this study. Analysis of BMPR2, ACVRL1 and KCNA5 genes was performed by polymerase chain reaction (PCR) and direct sequencing. Fifty one nucleotide changes were detected in these genes in 40 of the 41 patients; only 22 of these changes, which were classified as pathogenic, have been detected in 21 patients (51.2%). Ten patients (62.5%) with idiopathic PAH and 10 (40%) with associated PAH showed pathogenic mutations in some of the three genes. Several clinical and hemodynamics parameters showed significant differences between carriers and non-carriers of mutations, being more severe in carriers: mean pulmonary artery pressure (p = 0.043), pulmonary vascular resistence (p = 0.043), cardiac index (p = 0.04) and 6 minute walking test (p = 0.02). This differences remained unchanged after adjusting for PAH type (idiopathic vs non idiopathic). Conclusions: Pathogenic mutations in BMPR2 gene are frequent in patients with idiopathic and associated PAH group I. Mutations in ACVRL1 and KCNA5 are less frequent. The presence of these mutations seems to increase the severity of the disease

    Discrimination capacity in species distribution models depends on the representativeness of the environmental domain

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    Aim When faced with dichotomous events, such as the presence or absence of a species, discrimination capacity (the ability to separate the instances of presence from the instances of absence) is usually the only characteristic that is assessed in the evaluation of the performance of predictive models. Although neglected, calibration or reliability (how well the estimated probability of presence represents the observed proportion of presences) is another aspect of the performance of predictive models that provides important information. In this study, we explore how changes in the distribution of the probability of presence make discrimination capacity a context-dependent characteristic of models. For the first time,we explain the implications that ignoring the context dependence of discrimination can have in the interpretation of species distribution models

    The Calcium-Looping technology for CO2 capture: On the important roles of energy integration and sorbent behavior

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    The Calcium Looping (CaL) technology, based on the multicyclic carbonation/calcination of CaO in gas-solid fluidized bed reactors at high temperature, has emerged in the last years as a potentially low cost technology for CO2 capture. In this manuscript a critical review is made on the important roles of energy integration and sorbent behavior in the process efficiency. Firstly, the strategies proposed to reduce the energy demand by internal integration are discussed as well as process modifications aimed at optimizing the overall efficiency by means of external integration. The most important benefit of the high temperature CaL cycles is the possibility of using high temperature streams that could reduce significantly the energy penalty associated to CO2 capture. The application of the CaL technology in precombustion capture systems and energy integration, and the coupling of the CaL technology with other industrial processes are also described. In particular, the CaL technology has a significant potential to be a feasible CO2 capture system for cement plants. A precise knowledge of the multicyclic CO2 capture behavior of the sorbent at the CaL conditions to be expected in practice is of great relevance in order to predict a realistic capture efficiency and energy penalty from process simulations. The second part of this manuscript will be devoted to this issue. Particular emphasis is put on the behavior of natural limestone and dolomite, which would be the only practical choices for the technology to meet its main goal of reducing CO2 capture costs. Under CaL calcination conditions for CO2 capture (necessarily implying high CO2 concentration in the calciner), dolomite seems to be a better alternative to limestone as CaO precursor. The proposed techniques of recarbonation and thermal/mechanical pretreatments to reactivate the sorbent and accelerate calcination will be the final subjects of this review

    Study of association between Pre-Senile cataracts and the polymorphisms rs2228000 in XPC and rs1042522 in p53 in Spanish population

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    To determine if the presence of certain polymorphisms in the DNA repair gene XPC and the apoptosis inductor gene p53 is associated with pre-senile cataract development. Methods We have performed a retrospective study over three groups of patients. The group with presenile cataract formed by 72 patients younger than 55 with cataract surgery. The group with senile cataract formed by 101 patients older than 55 with cataract surgery. The group without cataract was formed by 42 subjects older than 55 without lens opacities. We analyzed the presence of SNP rs2228000 from XPC and rs1042522 from p53; and the relationship between risk factors such as smoking, alcohol intake, hypertension or diabetes. Results The comparison of the genotype distribution in XPC, within the different groups, did not show any statistically significant association in any of our analysis (p>0, 05). The comparison of the genotype distribution in p53 within the different groups did not show any statistically significant association (p>0, 05); except for the comparison between the pre-senile cataract group and the group with senile cataract where the genotype Pro/Pro (C/C) in the recessive inheritance model showed a higher risk for developing pre-senile cataract (p = 0, 031; OR = 1.04-15.97). This association decreased when we performed the analysis adjusting by the studied risk factors (p = 0.056). Conclusions Allelic variants in the gene XPC are not associated with an increased risk for developing pre-senile cataract. The presence of the genotype Pro/Pro in p53 might be associated with a major risk for developing pre-senile cataract

    Therapeutical Management for Ocular Rosacea

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    Purpose: The purpose of this study is to describe a case of ocular rosacea with a very complex evolution. Rosacea is a chronic dermatological disease that may affect the ocular structures up to 6-72% of all cases. This form is often misdiagnosed, which may lead to long inflammatory processes with important visual consequences for affected patients. Therefore, an early diagnosis and an adequate treatment are important. Methods: We report the case of a 43-year-old patient who had several relapses of what seemed an episode of acute bacterial conjunctivitis. Two weeks later, he developed a corneal ulcer with a torpid evolution including abundant intrastromal infiltrators and calcium deposits. He was diagnosed with ocular rosacea and treated with systemic doxycycline and topical protopic. Results: A coating with amniotic membrane was placed in order to heal the ulcer, but a deep anterior lamellar keratoplasty to restore the patient''s vision because of the corneal transparency loss was necessary. Conclusions: Ocular rosacea includes multiple ophthalmic manifestations ranging from inflammation of the eyelid margin and blepharitis to serious corneal affectations. A delayed diagnosis can result in chronic inflammatory conditions including keratinization and loss of corneal transparency, which lead to important visual sequelae for affected patients. (C) 2016 The Author(s) Published by S. Karger AG, Base

    Influence of ball milling on CaO crystal growth during limestone and dolomite calcination: Effect on CO2 capture at Calcium Looping conditions

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    The multicycle CO2 capture performance of CaO derived from the calcination of ball-milled limestone and dolomite have been tested under high temperature and high CO2 concentration environment for the first time. Here it is shown that the CO2 capture capacity of CaO is inversely related to the milling power applied to the starting mineral and the size of nascent CaO nanocrystals. In situ X-ray diffraction analysis used to follow the average crystallite size of CaCO3 and CaO during the calcination process as a function of temperature demonstrates that crystal growth is notably enhanced in a CO2-rich atmosphere for milled sorbents. Contrary to early reports suggesting improved reactivity towards carbonation of CaO from milled sorbents, promoted agglomeration, and crystal growth under these more “realistic” conditions lead to a severe deterioration of both capture capacity and recyclability, as observed from the multicyclic carbonation/calcination experiments. Yet the negative effect of milling is less pronounced in dolomite due to the constrained sintering effect of the inert MgO grains that results in smaller CaO crystallite sizes, reduced crystal growth rate, and improved performance. These results provide insight on the role of CaO crystallinity on the carbonation reaction, useful for devising strategies to improve sorbents performance.Peer reviewe

    PERFIL ACTUAL DEL AGRICULTOR ECOLÓGICO EN LA COMARCA DEL ALTO GUADALENTÍN (MURCIA)

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    Ecological farmer’s Profile of the Alto Guadalentín in the Murcia Region. Within the Murcia County, the Region of Alto Gudalentín represents 7.01% of the whole murcian farming dedicated to produce ecological products. In this project we analyse the farmer’s profile using data from the Alto Guadalentín Ecological Farming Council. The final result shows that 50% of the farmers in this region became ecological farmers from traditional farmers being the financial factor one of the key factors to switch from traditional to ecological farming. The higher percentage of ecological farmers of Alto Guadalentín, nearly 35%, are between 46 and 55 years old, 28% are between 36 and 45 years old and only 12.28% of the farmers in this region are under 36 years of age. Almost 87% of the Alto Guadalentín farmers don’t belong to any farming association.Dentro de la Comunidad de Murcia, la Comarca del Alto Guadalentín representa el 7,01% del total de la superficie murciana dedicada a agricultura ecológica. En este trabajo se analiza el perfil del agricultor ecológico en la Comarca del Alto Guadalentín para ello se realizaron encuestas al 74,03% de los agricultores de la zona, según los datos obtenidos del Consejo Agricultura Ecológica de la Región de Murcia. Los resultados obtenidos revelan que casi el 50% de los agricultores de la Comarca del Alto Guadalentín se inició como agricultor ecológico mediante un cambio del sistema de agricultura convencional hacia la agricultura ecológica, siendo el factor económico con casi el 57% uno de los principales motivos para pasar de un tipo de agricultura a otro. Por otro lado, el mayor porcentaje de los agricultores ecológicos del Alto Guadalentín (35%) se encuentran en un intervalo de edad entre 46 y 55 años. El 28% tienen entre 36 y 45 años y casi el 25% tienen una edad superior a 56 años. Solamente el 12,28% de los agricultores de la Comarca tienen edades inferiores a los 36 años. El 87% de los agricultores del Alto Guadalentín no pertenecen a ningún tipo de asociación

    Comparison of cohesive powder flowability measured by Schulze Shear Cell, Raining Bed Method, Sevilla Powder Tester and new Ball Indentation Method

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    Poor powder flow leads to many problems during manufacturing and can lead to inaccurate dosing and off-specification products. Powder flowability is commonly assessed under relatively high applied loads using shear cells by characterising the unconfined yield strength at a range of applied loads. For applied stresses below 1 kPa, it becomes increasingly difficult to obtain reliable values of the unconfined yield strength. The bulk cohesion and tensile strength of the powder are then obtained by extrapolating the yield locus to zero and negative loads, respectively. However, the reliability of this approximation for a given material is not known. To overcome this limitation, techniques such as the Raining Bed Method, Sevilla Powder Tester and the newly-developed Ball Indentation Method may be used. In this paper, we report our measurement results of the tensile strength of glass beads, α-lactose monohydrate and various sizes of fluid catalytic cracking powders determined by the Sevilla Powder Tester and Raining Bed Method and compare them with those inferred from the Schulze Shear Cell. The results of the latter are also compared with those of the Ball Indentation Method. The outcome suggests that in the case of shear cell tests, the extrapolation of the yield locus to lower or negative loads is unsafe. The ball indentation method enables the characterisation of highly cohesive powders at very low compressive loads; however extrapolation to negative loads is still not reliable. In contrast, the Sevilla Powder Tester and Raining Bed Methods are able to characterise the tensile strength directly, but high bulk cohesion poses difficulties as the internal bed failure needs to be analysed in order to reliably estimate the tensile strength. These methods provide a better understanding of powder flow behaviour at low stresses, thus enabling a greater control of manufacturing processes
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