Dynamical transitions in a pollination--herbivory interaction

Plant-pollinator associations are often seen as purely mutualistic, while in reality they can be more complex. Indeed they may also display a diverse array of antagonistic interactions, such as competition and victim--exploiter interactions. In some cases mutualistic and antagonistic interactions are carried-out by the same species but at different life-stages. As a consequence, population structure affects the balance of inter-specific associations, a topic that is receiving increased attention. In this paper, we developed a model that captures the basic features of the interaction between a flowering plant and an insect with a larval stage that feeds on the plant's vegetative tissues (e.g. leaves) and an adult pollinator stage. Our model is able to display a rich set of dynamics, the most remarkable of which involves victim--exploiter oscillations that allow plants to attain abundances above their carrying capacities, and the periodic alternation between states dominated by mutualism or antagonism. Our study indicates that changes in the insect's life cycle can modify the balance between mutualism and antagonism, causing important qualitative changes in the interaction dynamics. These changes in the life cycle could be caused by a variety of external drivers, such as temperature, plant nutrients, pesticides and changes in the diet of adult pollinators. Abstract Keywords: mutualism, pollination, herbivory, insects, stage-structure, oscillationsComment: 20 pages, 7 main figures, 2 appendix figure

Representaciones de género: una mirada (más bien) conservadora

El presente texto es un primer adelanto de los trabajos del “Taller de Análisis de las Representaciones en la Comunicación”, que desarrollamos con estudiantes de la Licenciatura en Comunicación de la Facultad de Estudios Superiores Acatlán, de la UNAM. El objetivo del Taller es analizar los procesos de mediación en los relatos de la comunicación pública, analizar el tratamiento que se da a varios temas y en distintos tipos de productos comunicativos, en televisión, radio, cine y revistas. El proyecto inició con el análisis de las representaciones de género en los relatos de la televisión. Se trata de revisar la cuestión de género tanto en productos con el formato de conductores (donde la ritualización ejerce gran importancia en el proceso mediacional), como en producciones de ficción (donde la operación mediacional recae en la mitificación). En los primeros, se comparará lo que se dice respecto al género como tema, con el comportamiento de las y los conductores: ¿hay o no congruencia entre lo que dicen y lo que hacen? En los relatos de ficción, se tratará de responder a la siguiente pregunta: ¿qué atributos y acciones propios del “ser hombre”, del “ser mujer”, se incluyen, cuáles se excluyen, cómo se relacionan, cómo se valoran en las representaciones de este tipo de relatos?The present text is a first advance of work from the “Representation Analysis in Communication Workshop”, developed with Communication students at the faculty of Higher Education in Acatlán, UNAM. The workshop’s goal is to analyze the processes of mediation in the stories of public communication, and analyze the treatment given to some topics and different kinds of communicative products in television, radio, films and magazines. The project began with the analysis of gender representations in television stories. The point is to go over the gender issue either in products conducted by a host (where ritualization exerts great importance in the mediation process), or in fictional productions (where mediational operation consists of mythification). In the first, a comparison will be made between what is said about gender as a topic, and the behaviour of the show’s host and hostess: is there consistency between what they say and what they do, or not? In fictional stories, the following questions will try to find an answer: what attributes and actions associated to “being a man” and “being a woman” are included? Which ones are excluded? How do they relate with one another? How are they valued in the representations of this kind of stories

Pasos en la nieve en la trayectoria poética de Jaime Siles

En la trayectoria poética de Jaime Siles, Pasos en la nieve (Tusquets 2004) constituye un reflejo de la evolución de un quehacer poético, que desde el diálogo con la tradición se dirige hacia un tipo de poesía más discursiva y meditativa. El poeta vuelve a un rasgo cultivado con anterioridad: la integración de la racionalidad reflexiva que incide en reflexiones filosóficas en torno de los grandes temas existenciales de la condición humana. Las referencias y temas utilizados, cercanos a la anécdota vital, trascienden la materialidad de lo vivido para ceder paso a una poesía metafísica, a una poética del conocimiento de amplia resonancia conceptual, en la que sobresale el gusto por la linealidad y exactitud, la presencia de términos de alta densidad conceptual y vocablos procedentes de la física o matemática. In his career as a poet, Jaime Siles shows with Pasos en la nieve (Tusquets 2004) the trace of poetry making. In this work, there is a dialogue with tradition to that ends up in more discursive and reflexive poetry. The poet comes back with a known feature: the integration of a reflexive rationality that deepens inside the great questions of the human being. The references and theme, close to vital anecdote, go from the ordinary living to a metaphysical poetry. A poetry of the knowledge appears that enhances the taste for lines and exactitude. Furthermore, a great number of terms from the mathematics and physic sciences are presented

Magnitude of formative flows in stream potholes

Although it is generally recognized that geomorphic work is tied to bedrock channel reshaping, the importance of low vs. high flow stages that cause the most geomorphic impact remains unclear. The objective of the research is to study the concept of “formative flow” in bedrock channels and determine, through morphological studies, if those flows have any impact on sculpted features such as potholes and how this relationship relates to various inputs such as flow stages (magnitude and frequency), shear stress, and sediment size. Here, we studied the distribution of the main pothole typologies and tried to understand why potholes are found along bedrock river channels. Specifically, we examined stream potholes from three locations along the Spanish Central System: Alberche, Tietar, and Manzanares rivers. We conducted the research by taking precise geometric measurements, classifying potholes, analyzing flow magnitude and frequency, and using a two-dimensional (2D) hydrodynamic model to assess key variables in Manzanares river. This research demonstrated that bankfull depths completely cover all pothole typologies in all the analyzed sites but are not sufficient to achieve its formative flow depth (FFD). Using a detailed 2D hydrodynamic model in Manzanares river, we discovered that dimensions of cylindrical potholes are closely related to bankfull discharge and that this depth is connected to FFD. Other potholes, such as erosive-compound and erosive-lateral, are historical remnants, and their shapes are not related to any particular FFD and are likely associated with rare events and catastrophic breaks. A collection of laterals that exhibit FFD near bankfull flows appear to represent a part of the recent evolution of a knickpoint. To summarize, it can be inferred from the findings that the utility of morphological analysis in conjunction with the 2D hydrodynamic model is to examine the fraction of erosional/active features to determine the degree of senescence and/or change in natural conditions in a river reach.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUERegional Government of Madrid (Spain)pu

Experimental Transmission of African Swine Fever (ASF) Low Virulent Isolate NH/P68 by Surviving Pigs

African swine fever (ASF) has persisted in Eastern Europe since 2007, and two endemic zones have been identified in the central and southern parts of the Russian Federation. Moderate- to low-virulent ASF virus isolates are known to circulate in endemic ASF-affected regions. To improve our knowledge of virus transmission in animals recovered from ASF virus infection, an experimental in vivo study was carried out. Four domestic pigs were inoculated with the NH/P68 ASF virus, previously characterized to develop a chronic form of ASF. Two additional in-contact pigs were introduced at 72 days post-inoculation (dpi) in the same box for virus exposure. The inoculated pigs developed a mild form of the disease, and the virus was isolated from tissues in the inoculated pigs up to 99 dpi (pigs were euthanized at 36, 65, 99 and 134 dpi). In-contact pigs showed mild or no clinical signs, but did become seropositive, and a transient viraemia was detected at 28 days post-exposure (dpe), thereby confirming late virus transmission from the inoculated pigs. Virus transmission to in-contact pigs occurred at four weeks post-exposure, over three months after the primary infection. These results highlight the potential role of survivor pigs in disease maintenance and dissemination in areas where moderate- to low-virulent viruses may be circulating undetected. This study will help design better and more effective control programmes to fight against this disease.EU project, ASFORCE Targeted Research Effort on African Swine Fever (KBBE.2012.1.3-02, 311931) and the European Union Reference laboratory for ASF (grant no UE- LR PPA/03).Peer Reviewe

Performance evaluation of two slow-medium growing chicken strains maintained under organic production system during different seasons

A total of 160 1-day-old medium-growing male chicks (Gallus gallus domesticus) were raised for 120 days in a certified organic farming system. A total of two strains were studied (Coloryield, CY; RedBro, RB). Overall, two weather periods were considered based on the outdoor temperature, being S1 colder than S2. In total, 40 chicks per strain were assigned to each period (n = 80). Chickens were fed ad libitum with the same organic feeds. In the first month, chickens were kept indoors and, from day 30, they had access to the pasture. Slaughter live weight (LW), average daily gains, (ADG), the feed conversion ratio (FCR), and mortality rates did not differ between the two strains. LW was (p < 0.05) higher in the S1 and a trend (p = 0.084) was observed for ADG, which was higher in S1. No differences were found for feed intake, FCR, and mortality rates between weather periods. There were no differences for coefficient of variation (CV) between the strains studied, nevertheless, CV for LW in S2 was increased. Differences in the productive performance between these strains raised in organic production systems were slight. However, chickens raised in S1 had a better performance. It would be preferable to raise chickens in these weather conditions whenever possible. © 2021 by the authors. Licensee MDPI, Basel, Switzerland