La argumentación en estudiantes de grado noveno cuando realizan actividades de generalización

El uso de la argumentación en el aula de matemáticas ha sido objeto de estudio y de vital importancia en el campo de la educación matemática. En este trabajo queremos describir la forma en que algunas actividades de generalización pueden potenciar los procesos de argumentación de los estudiantes dentro de nuestras prácticas pedagógicas. Se rediseñaron y ajustaron algunas tareas sobre generalización, las cuales se implementaron en cursos de matemáticas de grado noveno de dos instituciones educativas, una en Bogotá y otra en Soacha, Cundinamarca. Estas tareas permitieron evidenciar nuevas formas de desarrollar la actividad matemática en el aula y de fortalecer el desarrollo de habilidades argumentativas en los estudiantes

Evolution of nestling faeces removal in avian phylogeny

Nest sanitation-related traits have often been explained at the intraspecific level as reducing the probability of infection or detection by predators and parasites, but its evolution within the avian phylogeny is still poorly understood. We compiled detailed information of such traits for more than 400 bird species and, by means of modern comparative methodologies, we reconstructed the evolution of adults' contribution to removing their offspring's faeces and the production of faecal sacs by nestlings. Furthermore, because the functional hypotheses used to explain nest sanitation behaviour assume potential effects of brood size, body mass, nestling period and diet, we explored the association between these traits and those related to nest sanitation in a phylogenetically controlled framework. Our results suggest that parental removal of nestling faeces has driven the evolution of faecal sacs, while the ancestral states involved birds with faecal sacs removed by parents. These results support the long-held idea that faecal sacs facilitate the removal of faeces by parents. Moreover, we found that animal diets and small body sizes have favoured the evolution of faecal sacs suggesting the existence of some chemical and physical constraints in relation to the evolution of the mucous covering. Our results highlight the importance of nest sanitation in the evolution of birds and their life history characteristicsJ.D.I. was financed by a postdoctoral contract (TAHUB-104) from the program ‘Andalucía Talent Hub’ (cofunded by the European Union's Seventh Framework Program Marie Skłodowska-Curie actions (COFUND) and the regional Government of Andalucía). Funding was partially provided by the Spanish Ministerio de Economía y Competitividad (European funds (FEDER)) (CGL2013-48193-C3-1-P).Peer reviewe

Functional explanation of extreme hatching asynchrony: Male Manipulation Hypothesis

Hatching asynchrony in birds is considered an adaptation to facilitate brood reduction because under conditions of food scarcity, the smallest nestling usually dies soon after hatching, thereby minimizing parental effort. However, in species with extreme hatching asynchrony, the last hatchlings paradoxically experience a very low probability of survival and death can take so long that it can hardly be considered an adaptation. Here, we propose and experimentally tested a new adaptive hypothesis explaining the brood reduction paradox, namely the “Male Manipulation Hypothesis”. Our hypothesis suggests that by inducing asynchronous hatching, females increase the feeding requirements of the brood, which will induce males to increase provisioning effort. In addition, females may extend the period of male manipulation by feeding the smallest nestling just enough to sustain life. Our study showed that male common blackbirds (Turdus merula) increased their effort (i.e., number of food items per hour) in experimental asynchronous broods compared to synchronous broods, while females reduced their contribution, as predicted by the hypothesis

MTO with SAPO-34 in a Fixed-Bed reactor: deactivation profiles

Methanol-to-olefins is a promising process that has attracted the attention of many research groups in the last years. Zeolites are the primary catalyst for this process, and SAPO-34 is one of the most used because of its high selectivity toward C2-C4 olefins. As a drawback, it deactivates quickly and forces the process to work alternately using reaction and regeneration cycles. The mechanism by which SAPO-34 deactivates is still on debate, and further research needs to be done. In this study, the evolution of the deactivation profile for an SAPO-34-based catalyst was studied in a fixed-bed reactor. To achieve that, the catalyst bed was extracted after each experiment and divided in sections of 2 cm. For each section, CO2 adsorption, thermogravimetric analysis, and ammonia temperature-programmed desorption were performed

Baile y cuerpo: las formas más perfectas de comunicación

En el ámbito artístico, Diego Alejandro Galindo Soler es conocido por el sobrenombre “Galo”. Comenzó a bailar desde los tres años, gracias a su señora madre Olga Lucía Soler Lara, “ella me inculco la danza ya que era profesora de baile en el colegio Alberto Lleras Camargo”, comenta Diego Alejandro allí en el grupo de danzas Puertas del Sol - Un espacio para la vida. A los 4 años dio inicio a su ciclo de formación en las danzas tradicionales de diferentes regiones: desde la Andina, bailes típicos del bambuco, el sanjuanero huilense y tolimense, y vueltas antioqueñas, entre otros; de la región Caribe, baile Carnaval de Barranquilla, cien pies, cumbias, garabatos y gaitas; del Pacífico, contradanza y jota

La terminación automática del contrato de seguro por mora en el pago de la prima

En la presente monografía se analizan 3 decisiones, una del Consejo de Estado y las demás de la Corte Suprema de Justicia, en torno a la obligación del tomador del seguro, de pagar la prima y las consecuencias jurídicas de la mora, dependiendo del modelo aseguraticio, así como algunos aspectos adyacentes. Se revisan las principales diferencias normativas, relacionadas con dicha regla general, entre los seguros de cumplimiento, los de vida, y el seguro de automóviles. Se aclara la naturaleza jurídica del seguro de cumplimiento entre particulares y se expone la fundamentación de su tratamiento especial normativo, con las argumentaciones tanto a nivel jurisprudencial como en la doctrina nacional y los comentarios del autor de este documento. La relevancia de este estudio radica en que con las argumentaciones expuestas se nutren las diferentes posturas sobre la materia con el propósito de determinar cuál es la posición dominante del sector y de esta manera reducir las controversias entre las partes, que afectan a diario sus relaciones comerciales y a la vez genera desconfianza para el mercado de los seguros. Por lo anterior, se pretende que este documento sea una referencia no solo para juristas, sino que va dirigido también a personas que se relacionen o se vayan a relacionar con los seguros y que sirva para evitar posibles litigios sobre estos temas o de lo contrario, con el fin de que tengan en cuenta los fundamentos que aquí se presentan.In this monograph, three decisions are analyzed, one of the Council of State and the other of the Supreme Court of Justice, regarding the obligation of the policyholder, to pay the premium and legal consequences of arrears, depending on the insurance model , as well as some adjacent aspects. The main regulatory differences, related to this general rule, are reviewed between compliance insurance, life insurance, and motor insurance. It clarifies the legal nature of the insurance of compliance between prívate individuáis and explains the basis of its special normative treatment, with the arguments both at jurisprudential level and in the national doctrine and the comments of the author of this document. The relevance of this study lies in the fact that, with the above arguments, the different positions on the subject are nurtured in order to determine the dominant position of the sector and thus reduce the controversies between the parties, which affect their trade relations on a daily basis and at the same time generates distrust for the insurance market. For the above, it is intended that this document is a reference not only for lawyers, but also for people who are related or going to relate to insurance and who serves to avoid possible litigation on these issues or otherwise, in order to take into account the fundamentáis presented here.Especialista en Derecho de SegurosEspecializació

Fecal sacs attract insects to the nest and provoke an activation of the immune system of nestlings

Background: Nest sanitation is a widespread but rarely studied behavior in birds. The most common form of nest sanitation behavior, the removal of nestling feces, has focused the discussion about which selective pressures determine this behavior. The parasitism hypothesis, which states that nestling fecal sacs attract parasites that negatively affect breeding birds, was proposed 40 years ago and is frequently cited as a demonstrated fact. But, to our knowledge, there is no previous experimental test of this hypothesis. Results: We carried out three different experiments to investigate the parasitism hypothesis. First, we used commercial McPhail traps to test for the potential attraction effect of nestling feces alone on flying insects. We found that traps with fecal sacs attracted significantly more flies (Order Diptera), but not ectoparasites, than the two control situations. Second, we used artificial blackbird (Turdus merula) nests to investigate the combined attraction effect of feces and nest materials on arthropods (not only flying insects). Flies, again, were the only group of arthropods significantly attracted by fecal sacs. We did not detect an effect on ectoparasites. Third, we used active blackbird nests to investigate the potential effect of nestling feces in ecto- and endoparasite loads in real nestlings. The presence of fecal sacs near blackbird nestlings did not increase the number of louse flies or chewing lice, and unexpectedly reduced the number of nests infested with mites. The endoparasite prevalence was also not affected. In contrast, feces provoked an activation of the immune system as the H/L ratio of nestlings living near excrements was significantly higher than those kept under the two control treatments. Conclusions: Surprisingly, our findings do not support the parasitism hypothesis, which suggests that parasites are not the main reason for fecal sac removal. In contrast, the attraction of flies to nestling feces, the elevation of the immune response of chicks, and the recently described antimicrobial function of the mucous covering of fecal sacs suggest that microorganisms could be responsible of this important form of parental care behavior (microbial hypothesisPeer reviewe

Egg-recognition abilities in non-incubating males:Implications for the evolution of anti-parasitic host defenses

In the field of brood parasitism, it has been traditionally assumed that only the incubating sex rejects parasitic eggs, but this assumption has been rarely explored despite its important implications for the evolutionary relationship between brood parasites and hosts. Here, we used information on previous egg-rejection experiments to explore the recognition abilities of both males and females of Eurasian blackbirds Turdus merula towards experimental eggs with a variable degree of mimicry. We found that both sexes recognized non-mimetic eggs, supporting the idea that visits to the nest can favor the evolution of rejection abilities. In contrast, only females recognized mimetic eggs, indicating that although recognition abilities can evolve in both sexes, they are subsequently refined in females probably due to their more frequent interaction with parasitic eggs. Clutch size affected nest attendance since females, but not males, spent more time at the nest and visited it more frequently in larger clutches. Finally, our recordings showed that blackbird males are able not only to recognize, but also to eject parasitic eggs. Our results provide new insights into the main anti-parasitic defense in birds, egg rejection, and highlight the need of considering the role of the non-incubating sex in egg-rejection studies.Significance statementGiven the high costs associated to avian brood parasitism, both sexes are expected to evolve anti-parasitic defenses. However, in those species in which only females incubate, females have traditionally been assumed to be the responsible for egg rejection. Here, using the Eurasian blackbird (Turdus merula), we investigated the existence of egg-rejection abilities in non-incubating males and compared them to those exhibited by females. We found that males can recognize non-mimetic eggs, although their recognition abilities were less fine-tuned compared to females, who also recognized mimetic eggs. Even though females were the responsible for most documented egg-ejection events, recordings confirmed that males could also be involved in egg ejection, which could have important implication for the evolution of anti-parasitic defenses in host populations