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Ground-coupled natural circulating devices (Thermosiphons): A review of modeling, experimental and development studies
No full textCompared to conventional ground heat exchangers that require a separate pump or other mechanical devices to circulate the heat transfer fluid, ground coupled thermosiphons or naturally circulating ground heat exchangers do not require additional equipment for fluid circulation in the loop. This might lead to a better overall efficiency and much simpler operation. This paper provides a review of the current published literature on the different types of existing ground coupled thermosiphons for use in applications requiring moderate and low temperatures. Effort has been focused on their classification according to type, configurations, major designs, and chronological year of apparition. Important technological findings and characteristics are provided in summary tables. Advances are identified in terms of the latest device developments and innovative concepts of thermosiphon technology used for the heat transfer to and from the soil. Applications are presented in a novel, well-defined classification in which major ground coupled thermosiphon applications are categorized in terms of medium and low temperature technologies. Finally, performance evaluation is meticulously discussed in terms of modeling, simulations, parametric, and experimental studies. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Transformation strategy for computer training: Towards the skills development in basic and secondary education for industry 4.0 in Medellín-Colombia [Estrategia de transformación para la formación en informática: Hacia el desarrollo de competencias en educación básica y media para la industria 4.0 en Medellín – Colombia]
No full textComputing has made substantial progress in society, due to the transformative role that technology has as the axis of development. Even though education has also been permeated by the transformations of technology and the evolution of computer science, the affectation and curricula transformation is very low, especially in basic and secondary levels. Thus, in Colombia computer training continues being conceived as a complementary subject to other areas that seek the training of technology consumers rather than its creators. This work proposes a transformation strategy for computer training in primary and secondary education institutions, oriented towards the development of competences for Industry 4.0, focused on creative and computational thinking. This proposal has two key elements: curricular design, and didactic design as well as a Training Ecosystem in institutions at these levels. © 2020, Associacao Iberica de Sistemas e Tecnologias de Informacao. All rights reserved
Trichoderma asperellum as a preventive and curative agent to control Fusarium wilt in Stevia rebaudiana
No full textStevia has been introduced in many countries for the production of sugar-free sweeteners. Concurrently, several emerging pathogens have been described in this plant host. One of the latest has been Fusarium oxysporum, a well-known soil-borne pathogen causing vascular wilt in many plants. Classical methods to control Fusarium wilt are being questioned, and biocontrol agents are gaining importance as part of integrated approaches to manage the disease. Different species of Trichoderma have been described as optimal candidates to control F. oxysporum. However, their effectiveness is generally reported in annual plants and efficacy depends on the application protocol. We conducted an experiment to assess the preventive or curative potential of the rhizospheric T. asperellum UDEAGIEM-H01 strain against F. oxysporum on rooted cuttings of S. rebaudiana. After 33 days, F. oxysporum-infected stevia seedlings were severely affected (90% of disease incidence). Contrastingly, only 10% of the T. asperellum pre-treated plants and 70% of the post-treated showed Fusarium wilt symptoms. Dual confrontation assays proved the potential antagonistic effect of T. asperellum against F. oxysporum and five additional soil-borne pathogens affecting S. rebaudiana. Further in vitro tests revealed that this new strain of T. asperellum produces phytohormones (salicylic and jasmonic acid), and the secretion of cell-wall degrading enzymes (chitinases and cellulases); this ability could be related to its antagonistic and mycoparasitic activity. The present work concluded that T. asperellum UDEAGIEM-H01 has a high ability, mainly as a preventive agent, to control F. oxysporum in stevia plants showing further antagonistic effects and mycoparasitism on other fungal pathogens. © 2021 Elsevier Inc
Limits on point-like sources of ultra-high-energy neutrinos with the Pierre Auger Observatory
No full textData for wetlandscapes and their changes around the world
No full textGeography and associated hydrological, hydroclimate and land-use conditions and their changes determine the states and dynamics of wetlands and their ecosystem services. The influences of these controls are not limited to just the local scale of each individual wetland but extend over larger landscape areas that integrate multiple wetlands and their total hydrological catchment-the wetlandscape. However, the data and knowledge of conditions and changes over entire wetlandscapes are still scarce, limiting the capacity to accurately understand and manage critical wetland ecosystems and their services under global change. We present a new Wetlandscape Change Information Database (WetCID), consisting of geographic, hydrological, hydroclimate and land-use information and data for 27 wetlandscapes around the world. This combines survey-based local information with geographic shapefiles and gridded datasets of large-scale hydroclimate and land-use conditions and their changes over whole wetlandscapes. Temporally, WetCID contains 30-year time series of data for mean monthly precipitation and temperature and annual land-use conditions. The survey-based site information includes local knowledge on the wetlands, hydrology, hydroclimate and land uses within each wetlandscape and on the availability and accessibility of associated local data. This novel database (available through PANGAEA https://doi.org/10.1594/PANGAEA.907398; Ghajarnia et al., 2019) can support site assessments; cross-regional comparisons; and scenario analyses of the roles and impacts of land use, hydroclimatic and wetland conditions, and changes in whole-wetlandscape functions and ecosystem services.. © 2005 IEEE Computer Society. All rights reserved
Attitude Towards Sport Practice: What Makes an Individual Continued Practice of Sport?
No full textSport practice is conditioned by different factors; previous studies have shown that the attitude towards physical activity and sports practice is largely conditioned by the individual. This study proposes to examine whether the classic model of the theory of planned behaviour reinforces the main motivations for people to adhere to a sport practice. An empirical model based on the classic model of the theory of planned behaviour was proposed, adding three motivational variables to sport practice. A sample was composed of 1008 valid questionnaires collected online in Spain and Colombia. The analysis of the data was performed using the partial least squares technique using the Smart PLS 3.0 statistical programme. The proposed model presents a statistical validity that proves that the practice of physical and sporting activity is determined by the individual’s evaluation of their abilities and perceptions and their relationship with the motivations generated by continuing the practice of physical or sports activity, consequently how adherence is generated. © 2020, Associação Brasileira de Psicologia
A COMPLEX ORDER MODEL of ATRIAL ELECTRICAL PROPAGATION from FRACTAL POROUS CELL MEMBRANE
No full textCardiac tissue is characterized by structural and cellular heterogeneities that play an important role in the cardiac conduction system. Under persistent atrial fibrillation (persAF), electrical and structural remodeling occur simultaneously. The classical mathematical models of cardiac electrophysiological showed remarkable progress during recent years. Among those models, it is of relevance the standard diffusion mathematical equation, that considers the myocardium as a continuum. However, the modeling of structural properties and their influence on electrical propagation still reveal several limitations. In this paper, a model of cardiac electrical propagation is proposed based on complex order derivatives. By assuming that the myocardium has an underlying fractal process, the complex order dynamics emerges as an important modeling option. In this perspective, the real part of the order corresponds to the fractal dimension, while the imaginary part represents the log-periodic corrections of the fractal dimension. Indeed, the imaginary part in the derivative implies characteristic scales within the cardiac tissue. The analytical and numerical procedures for solving the related equation are presented. The sinus rhythm and persAF conditions are implemented using the Courtemanche formalism. The electrophysiological properties are measured and analyzed on different scales of observation. The results indicate that the complex order modulates the electrophysiology of the atrial system, through the variation of its real and imaginary parts. The combined effect of the two components yields a broad range of electrophysiological conditions. Therefore, the proposed model can be a useful tool for modeling electrical and structural properties during cardiac conduction. © 2020 World Scientific Publishing Company
The separation of powers and the system of checks and balances in the united states: From hamilton, madison and marshall's dream to the threat of the imperial presidency [La separación de poderes y el sistema de pesos y contrapesos en estados unidos: Del sueño de hamilton, madison y marshall a la amenaza de la presidencia imperial]
No full textThe objective of this paper is to determine whether, after 230 years of the Constitution of the United Stated of America, the pillars of the separation of powers and the system of checks and balances that authors like Hamilton, Madison and Marshall helped design or, otherwise, whether what some authors call "the imperial presidency" has been implemented. The methodology used is of a dogmatic historical nature. The conclusion is that the personality of the president of the American Union has become a noninstitutionalized limit which is extremely dangerous and contradicts the very idea of the Rule of Law. Facing the threat of the "president emperor", today it is unavoidable to remember the principles that inspired the Constitution of the United States and the limits it imposes on the different powers, including the executive. © 2018 Universidad de Caldas.El objetivo del presente trabajo es determinar si pasados 230 años de la Constitución de los EE. UU. se conservan los pilares de la separación de poderes y el sistema de pesos y contrapesos que autores como Hamilton, Madison y Marshall ayudaron a diseñar o en caso contrario si se ha implementado lo que algunos autores llaman "la presidencia imperial". La metodología utilizada es de carácter histórico dogmática. La conclusión es que la personalidad del presidente de la Unión Americana se ha convertido en un límite no institucionalizado, lo que es sumamente peligroso y contradice la idea misma del Estado de derecho. Frente a la amenaza del "presidente emperador", hoy se hace ineludible recordar los principios que inspiraron la Constitución de los EE. UU. y los límites que impone a los diferentes poderes, incluyendo el ejecutivo. © 2018 Universidad de Caldas
Tariff barriers and non-tariff barriers: Appraising Colombia’s protectionism
No full textTariff barriers (TBs) are regulated under the provisions of the General Agreement on Tariffs and Trade (GATT), such as the most-favoured-nation treatment article, which establishes that trade concessions granted to one member are applied immediately and without conditions to all other members. Likewise, the schedule of concessions on goods, which indicates that all trade concessions made by members must be reported under the legal agreement’s ‘bound’ rates. Then, if one World Trade Organization (WTO) member raises applied tariffs above their bound level, any WTO member can sue the country for this action. However, on the other hand, the non-tariff barriers (NTBs) are more complex to regulate due to a state’s ability to adopt many different new measures, which makes the measures hard to identify as barriers. Furthermore, the opacity of many NTBs also makes enforcement of regulations a complicated international endeavour. Thus, the international trading system assumes that there will be essential challenges and seeks to develop explicit provisions for this kind of protectionism. This paper, which is based on the findings of a comprehensive review of Colombia’s situation, provides a general explanation of TBs and NTBs as protectionist measures within the foreign trade of this Latin American country. In doing so, the research identifies the TBs and NTBs currently adopted, the effects of these barriers on this economy, and the sectors that are meaningfully affected by these measures. © 2020, International Network of Customs Universities. All rights reserved
Mujeres indígenas en el marco del conflicto armado en el Chocó : protección efectiva, liderazgos y construcción de paz
Get PDFPretende visibilizar las luchas y liderazgos que las mujeres indígenas han venido realizando en pro de sus garantías individuales y colectivas, dentro del conflicto armado en el departamento del Chocó, identificando factores que obstaculizan la protección efectiva de sus derechos, al igual que avances, retrocesos y dificultades frente a los procesos de inclusión, empoderamiento y construcción de una paz estable y duradera para sus territorios. Así, para el desarrollo de este trabajo, se empleó una investigación cualitativa, bajo un diseño metodológico en el que se combinaron distintas técnicas para la recolección de la información, como entrevistas y derechos de petición, de este modo, poder responder al interrogante ¿Cuáles son las barreras que han obstaculizado la protección de las mujeres indígenas en el marco del conflicto armado en el Chocó? Por cuanto, la justificación de esta investigación se desarrolla en las siguientes líneas, soportadas en una revisión documental, normativa y jurisprudencial.Magíster en Derechos Humanos y Derecho Internacional HumanitarioMaestrí