Este trabajo surge a partir de la investigación general de las técnicas hidropónicas teniendo en cuenta sus ventajas y desventajas para de esta forma poder encontrar aquel factor determinante a través de una comparación de técnicas hidropónicas que permitan clasificarlas y escoger la mejor opción que genere menos impacto ambiental negativo y demuestre ser más productivo en los entornos urbanos. Adicionalmente, un factor determinante en las ciudades es su espacio limitado por lo que la mejor opción también deberá incluir un (...) óptimo manejo del espacio que permita a casi cualquier individuo poder aplicarlos desde su entorno sin recurrir a excesivas modificaciones. Como principal resultado se escogió a la Hidroponía recirculante como método predominante por los excelentes resultados que se obtienen con relación a los demás, adicionalmente, este puede ser fácilmente aplicado en los ambientes urbanos por su versatilidad y buen manejo de recursos. Palabras Clave: Hidroponia, ambiente, urbano, comparativa, técnicas, cultivo. Referencias [1]J. López, «La producción hidropónica de cultivos,» IDESIA, vol. 36, nº 2, pp. 139-141, 2018. [2]J. Lee, A. Rahman, J. Behrens, C. Brennan, B. Ham, H. Seok Kim, C. Won, S. Yun, H. Azam y M. Kwon, «Nutrient removal from hydroponic wastewater by a microbial consortium,» New Biotechnology, vol. 41, pp. 15-24, 2018. [3]H. Ku, C. Tiong, A. Suresh y B. Ong, «“Active” hydroponic greenhouse system to kick-start and augment reforestation program through carbon sequestration e an experimental and theoretical feasibility study,» Journal of Cleaner Production, vol. 129, pp. 637-646, 2016. [4]J. Beltrano y D. Gimenez, Cultivo en hidroponía, Buenos Aires: Universidad de la Plata, 2015. [5]L. Ramírez, M. Pérez, P. Jiménez, H. Giraldo y E. Gómez, «Evaluación preliminar de sistemas acuapónicos e hidropónicos en cama flotante para el cultivo de orégano,» Revista Facultad de Ciencias Básicas, vol. 7, nº 2, pp. 242-259, 2011. [6]S. Hosseinzadeh, D. Testai, M. BKheet y J. De Graeve, «Degradation of root exudates in closed hydroponic systems using UV/H2O2: Kinetic investigation, reaction pathways and cost analysis,» Science of the Total Environment, vol. 1, pp. 1-9, 2019. [7]N. Camarena, A. Rojas y M. Santos, «Fluoride bioaccumulation by hydroponic cultures of camellia,» Chemosphere, vol. 136, pp. 56-62, 2015. [8]W. Wang, Y. Ma, L. Fu, Y. Cui y M. Yaqoob, «Physical an mechanical properties of hydroponic lettuce for automatic harvesting,» Informatión processing in agriculture, vol. 1, pp. 2214-3173, 2020. [9]M. Zárate, Manual de Hidroponia, Coyoacán: Universidad Autónoma de Mexico, 2014. [10]S. Magwaza, L. Magwaza, A. Odindo y C. Buckley, «Partially treated domestic wastewater as a nutrient source for tomatoes grown in a hydroponic system: effect on nutrientabsorption and yield,» Heliyon, vol. 6, nº 12, pp. 2405-8440, 2020. [11]C. ARANO, «Hidroponía: Algunas paginas de historia,» Tecnología de Producción, nº 58, pp. 24-32, 2007. [12]G. Guzmán, Hidroponia en Casa: Una actividad familiar, Costa Rica: Ministerio de Agricultura y ganaderia, 2004. [13]J. Gilsanz, HIDROPONIA, Montevideo : Unidad de Comunicación y Transferencia de Tecnología, 2007. [14]C. Miller, «El debate de hidroponia orgánica: Perspectivas norteamericanas sobre si la producción hidropónica merece ser certificada como orgánica.,» Productores de Hortalizas, nº 6, pp. 36-38, 2017. [15]A. Herrera, «Manejo de la solución nutritiva en la producción de tomate en hidroponía,» Terra Latinoamericana, vol. 17, nº 3, pp. 221-229, 1999. [16]C. Espinal y D. Matulić, «Recirculating Aquaculture Technologies,» Biomedical and Life Sciences, pp. 35-76, 2020. [17]H. Resh, «Técnicas de cultivo con flujo laminar de nutrientes,» de Cultivos Hidroponicos, España, Mundi-Prensa, 2001, pp. 35-37. [18]P. Blanca y L. Teresa, «Sistemas recirculantes y su interés en el cutlivo de ornamentales,» Tecnología de producción, nº 35, pp. 34-36, 2006. [19]C. Magán, «Recirculación de las soluciones nutritivas, Manejo y Control Microbiologico,» InfoAgro, nº 2, pp. 1-2, 2016. [20]S. Goddek, A. Joyce, B. Kotzen y M. Dos-Santos, «Aquaponics and Global Food Challenges,» Aquaponics Food Production Systems. Springer, vol. 1, nº 1, pp. 3-17, 2019. [21]S. G. Verdoliva, D. Gwyn Jones, A. Detheridge y P. Robson, «Controlled comparisons between soil and hydroponic systems reveal increased water use efficiency and higher lycopene and β-carotene contents in hydroponically grown tomatoes,» Scientia Horticulturae, pp. 3002-4238, 2020. [22]A. Chaudhry y V. Mishra, «A Comparative Analysis of Vertical Agriculture Systems in Residential Apartments, » de 2019 Advances in Science and Engineering Technology International Conferences, Dubai, United Arab Emirates, United Arab Emirates, 2019. [23]T. Mazhar, G. Jianmin, L. Imran, S. Kashif, Q. Waqar, S. Sher y C. Jiedong, «Modern plant cultivation technologies in agriculture under controlled nvironment: a review on aeroponics,» Journal of Plant Interactions, vol. 13, nº 1, pp. 338-352, 2012. [24]K. Janiak, A. Jurga, J. Kuźma, W. Breś y M. Muszyński, «Surfactants effect on aeroponics and important mass balances of regenerative life support system – Lettuce case study,» Science of the Total Environment, vol. 718, nº137324, pp. 1-12, 2020. [25]F. Rahman, I. Jahan, R. Biplob, N. Farhin y J. Uddin, «Automated Aeroponics System for Indoor Farming using Arduino,» de 2018 Joint 7th International Conference on Informatics, Electronics & Vision and 2018 2nd International Conference on Imaging, Vision & Pattern Recognition, Kitakyushu, Japan, 2018. [26]M. Caldeyro Stajano, «La Hidroponía Simplificada como Tecnología apropiada, para implementar la Seguridad Alimentaria en la Agricultura Urbana.,» Cuadernos del CEAgro, nº 8, pp. 71-76, 2006. (shrink)

The remarkable modern speculations concerning non-Euclidean sorts of space, of which Prof. Helmholtz gave some account in No. III. of MIND, are likely to be hailed as one of the chief difficulties with which the Kantian theory of space will have to deal. Digital edition compiled by Gabriele Dörflinger. Heidelberg University Library.

111 Cid, que en buena hora babia nacido, pasó de este siglo en «el día de ginqttaesma» o domingo de Pentecostés, 29 de mayo del año 1099. Las Gesto Francarum o crónicas de las Cruzadas señalan esta misma fecha para el inicio de [a marcha y asedio que concluyeron con la toma de Jerusalén por los cristianos. Esta coincidencia de fechas no pudo pasar desapercibida al autor del Poema de Mio Cid. La gesta del Campeador cobraba un valor simbólico que (...) trascendía la geografía de sus hazañas por tierras castellanas hasta Valencia, enlazando con la de las Cruzadas en el extremo oriental de [a cristiandad frente al mismo adversario musulmán. (shrink)

A new theory of four-dimensional symmetry introduced by Hsu has been criticized as logically inconsistent. We answer the criticisms that have been raised and show that in fact this theory is not logically inconsistent.

Following the ideas of Poincaré, Reichenbach, and Grunbaum concerning the convention of setting up clock systems, we analyze clock systems and light propagation within the framework of four-dimensional symmetry. It is possible to construct a new four-dimensional symmetry framework incorporatingcommon time: observers in different inertial frames of reference use one and the same clock system, which is located in any one of the frames. Consequently, simultaneity has a meaning independent of position and independent of frame of reference. A further consequence (...) is that the two-way speeds of light alone are isotropic in any frame. By the choice of clock system there will be one frame in which the one-way speed of light is isotropic. This frame can be arbitrarily chosen. The difference between one-way speeds and two-way speeds of light signals is considered in detail. (shrink)

Van der Henst argues that the theory of mental models lacks a pragmatic component. He fills the gap with the notion that reasoners draw the most relevant conclusions. We agree, but argue that theories need an element of “nondeterminism.” It is often impossible to predict either what will be most relevant or which particular conclusion an individual will draw.

The theory of mental models and its computer implementations have led to crucial experiments showing that no standard logic—the sentential calculus and all logics that include it—can underlie human reasoning. The theory replaces the logical concept of validity (the conclusion is true in all cases in which the premises are true) with necessity (conclusions describe no more than possibilities to which the premises refer). Many inferences are both necessary and valid. But experiments show that individuals make necessary inferences that are (...) invalid, e.g., Few people ate steak or sole; therefore, few people ate steak. Other crucial experiments show that individuals reject inferences that are not necessary but valid, e.g., He had the anesthetic or felt pain, but not both; therefore, he had the anesthetic or felt pain, or both. Nothing in logic can justify the rejection of a valid inference: a denial of its conclusion is inconsistent with its premises, and inconsistencies yield valid inferences of any conclusions whatsoever including the one denied. So inconsistencies are catastrophic in logic. In contrast, the model theory treats all inferences as defeasible (nonmonotonic), and inconsistencies have the null model, which yields only the null model in conjunction with any other premises. So inconsistences are local. Which allows truth values in natural languages to be much richer than those that occur in the semantics of standard logics; and individuals verify assertions on the basis of both facts and possibilities that did not occur. (shrink)

We resolve the two problems that Hardman raises. The first problem arises from a misunderstanding: the crucial distinction is between one-model and multiple-model problems. The second problem illuminates a deeper principle: conclusions depend on the procedures for interpreting models. We describe an algorithm that obviates the problem and empirical work that reveals a new view of syllogistic reasoning.

Introduction: The decision of “do not attempt resuscitation” in the event of cardiopulmonary arrest is usually made when the patients are critically ill and cannot make an informed choice. Although, various professional bodies have published guidelines, little is know about the patients’ own views regarding DNAR discussion.Aim: The aim of this study was to determine patients’ attitudes regarding discussing DNAR before they are critically ill.Methods: A prospective study was performed in a general out patients department. A questionnaire was distributed to (...) consecutive outpatients along with an explanatory leaflet in the adult outpatient clinic.Results: 364 patients completed the questionnaire . 90% of respondents wanted all patients to be asked regarding DNAR decision at some point during a hospital admission. The majority would not find a DNAR discussion distressing. Only 10% would find it upsetting, however, 48% of these still wanted a discussion. 37% of respondents wanted to discuss DNAR decisions on admission; 32% in outpatients; 17% at consent for surgery, 14% when they are critically ill. 87% of respondents would not object to their relatives being involved in making decisions about their resuscitation status. However, only 12% of the subjects in the study had been involved in discussing the resuscitation status of a relative and 21% would not be comfortable to discuss a relative’s resuscitation status. Although 33% of patients preferred their resuscitation status to simply be documented within their clinical notes, 77% wanted it to be more easily accessible.Conclusions: This study suggests that contrary to current practice most patients want to discuss their DNAR status prior to becoming critically ill. This includes half of the small number that find it distressing to discuss. Although most patients are comfortable with relatives being involved in discussing DNAR, a significant proportion do not want their relatives to be asked. Furthermore, once a decision has been made, the majority of patients want it to be more accessible than current practice allows. (shrink)

The present paper explores the role of motivation to observe a certain outcome in people’s predictions, causal attributions, and beliefs about a streak of binary outcomes. In two studies we found that positive streaks lead participants to predict the streak’s continuation, but negative streaks lead to predictions of its end. More importantly, these wishful predictions are supported by strategic attributions and beliefs about how and why a streak might unfold. Results suggest that the effect of motivation on predictions is mediated (...) by a serial path via causal attributions to the teams at play and belief in the hot hand. (shrink)