Reaction-diffusion systems and pattern formation

Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2016, Director: Àlex HaroThis bachelor’s degree final thesis deals with the problem of pattern formation in living forms, with special interest in animal skin. Mathematically, this phenomenon is caused due to perturbations on a system of differential equations initially in equilibrium, the so-called reaction-diffusion system, which is time independent but it becomes spatially unstable when is perturbed. This spatial instability is the one which causes the pattern. Therefore, we have started this project obtaining this mathematical model and then studying under which conditions the system becomes spatially unstable. Particularly, these conditions were given by the mathematician Alan Turing in The Chemical Basis of Morphogenesis in 1952. Furthermore, another important point developed in this undergraduate thesis has been to apply this theory on animal body, particularly, to see how the geometry of the body affects the design of the resulting pattern (striped or spotted). Finally, we have made some simulations of the system of differential equations in adapted domains with the characteristics we want to emphasize of animal body (scale, thickness and curvature). In order to do them, we have designed three programs in C which approximate the solution of the system using the explicit scheme of a numerical method, the so-called finite difference method

Correlation between Low Temperature Adaptation and Oxidative Stress in Saccharomyces cerevisiae

Many factors, such as must composition, juice clarification, fermentation temperature, or inoculated yeast strain, strongly affect the alcoholic fermentation and aromatic profile of wine. As fermentation temperature is effectively controlled by the wine industry, low-temperature fermentation (10–15°C) is becoming more prevalent in order to produce white and “rosé” wines with more pronounced aromatic profiles. Elucidating the response to cold in Saccharomyces cerevisiae is of paramount importance for the selection or genetic improvement of wine strains. Previous research has shown the strong implication of oxidative stress response in adaptation to low temperature during the fermentation process. Here we aimed first to quantify the correlation between recovery after shock with different oxidants and cold, and then to detect the key genes involved in cold adaptation that belong to sulfur assimilation, peroxiredoxins, glutathione-glutaredoxins, and thioredoxins pathways. To do so, we analyzed the growth of knockouts from the EUROSCARF collection S. cerevisiae BY4743 strain at low and optimal temperatures. The growth rate of these knockouts, compared with the control, enabled us to identify the genes involved, which were also deleted and validated as key genes in the background of two commercial wine strains with a divergent phenotype in their low-temperature growth. We identified three genes, AHP1, MUP1, and URM1, whose deletion strongly impaired low-temperature growth.This work has been financially supported from the Spanish Government through MINECO and FEDER funds (AGL2013-47300-C3-3-R and PCIN-2015-143 grants) and from Generalitat Valenciana through PROMETEOII/2014/042 grant, awarded to JG. This study has been carried out in the context of the European Project ERA-IB “YeastTempTation” EG also thanks the Spanish government for an FPI grant BES-2011-044498.Peer reviewe

Reportaje multimedia. Una mirada social al estigma de las enfermedades mentales

Alrededor de 450 millones de personas padecen un trastorno mental en todo el mundo. Una cifra que irá en aumento en los próximos años, puesto que la Organización Mundial de la Salud (OMS) alerta del déficit en salud mental a nivel global, y advierte de que menos de la mitad de las personas que sufren algún trastorno mental recibe atención médica. Las cuatro causas principales de discapacidad entre las personas mayores de 5 años corresponden a trastornos mentales, siendo la depresión la primera causa por enfermedad. Aunque se han logrado grandes avances en la comprensión y el tratamiento de las enfermedades mentales, el estigma que las rodea aún persiste. Bajo el titular Deconstruyéndonos, se presenta un reportaje multimedia donde, se ha dado voz a enfermedades como la ansiedad, la depresión, la esquizofrenia y la bipolaridad, trastornos que afectan a más de un 10% de toda la población mundial, a través de diferentes historias de vida que necesitan ser escuchadas. Este TGF tiene como objetivo romper con los estigmas asociados a las enfermedades mentales y acabar con la desinformación existente en torno a la salud mental, a través de la elaboración de diferentes elementos como entrevistas audiovisuales, infografías, encuestas, audios y declaraciones de expertosAround 450 million people suffer from a mental disorder worldwide. A figure that will increase in the coming years, since the World Health Organization (WHO) has already warned of the mental health deficit on a global scale, as less than half of the people suffering from a mental disorder receive medical care. The four leading causes of disability among people over 5 years of age are mental disorders, being depression the main reason of disability due to illness. Although great advances have been reached in the understanding and the treatment of mental illnesses, the stigma surrounding them persists. Under the headline Deconstructing Us, diseases such as anxiety, depression, schizophrenia and bipolar, disorders, which affect more than 10% of the world's population, have been given a voice through different life stories that need to be heard. This multimedia report aims to break up with the stigmas related to mental illnesses and to put an end to the existing misinformation about mental health, through the elaboration of different elements such as audiovisual interviews, infographics, surveys, audios and experts claims.Departamento de Historia Moderna, Contemporánea y de América, Periodismo y Comunicación Audiovisual y PublicidadGrado en Periodism

Modular Planar Antenna at X-band for satellite communications

An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 [1] and ITU-R S.465-5 [2] for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarizatio

Portable low profile antenna at X-band

An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 and ITU-R S.465-5 for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band with a VSWR of 1.4:1. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarization

Aproximación a un estado del arte de la didáctica en la educación ambiental

RESUMEN: La didáctica en la educación ambiental se puede leer desde el proceso docente educativo en la educación ambiental, modelos pedagógicos y educación ambiental, modelos didácticos y educación ambiental, competencias docentes para la educación ambiental, el método en la educación ambiental, los medios didácticos en la educación ambiental y didáctica en la educación ambiental. El análisis de la información muestra que: Hay mucho por hacer en materia de modelos pedagógicos y modelos didácticos en educación ambiental y que la relativa información de métodos y medios deja inferir que es un enfoque instrumentalista y devela que hay un gran vacío y se hace necesario construir un análisis reflexivo

Box 2. The EU economies’ natural gas inventories in 2022 and 2023 under two hypothetical scenarios

Artículo de revistaThis early-release box was published on 16 Septembe

Product Design by Additive Manufacturing for Water Environments: Study of Degradation and Absorption Behavior of PLA and PETG

Additive manufacturing technologies are shifting from rapid prototyping technologies to end use or final parts production. Polymeric material extrusion processes have been broadly addressed with a specific definition of all parameters and variables for all different of technologies approaches and materials. Recycled polymeric materials have been studied due to the growing importance of the environmental awareness of the contemporary society. Beside this, little specific research has been found in product development applications for AM where the printed parts are in highly moisture environments or surrounded by water, but polymers have been for long used in such industries with conventional manufacturing approaches. This work focuses on the analysis and comparison of two different additively manufactured polymers printed by fused filament fabrication (FFF) processes using desktop-size printers to be applied for product design. The polymers used have been a recycled material: polyethylene terephthalate glycol (PETG) and polylactic acid (PLA). Degradation and water absorption behaviors of both materials are presented, analyzed and discussed in this paper, where different samples have been immersed in saturated solutions of water with maritime salt and sugar together with a control sample immersed in distilled water. The samples have been dimensionally and weight-controlled weekly as well as microscopically analyzed to understand degradation and absorption processes that appear in the fully saturated solutions. The results revealed how the absorption process is stabilized after a reduced number of weeks for both materials and how the degradation process is more remarked in the PLA material due to its organic nature

Efecto de promotores de crecimiento en Botryococcus braunii Kutzing 1849 a partir de diferentes cepas bacterianas

ABSTRACT: There are several strategies to improve the growth of microalgae in industrial processes. In recent years, one of them has gained strength to achieve this goal: the co-culture with bacteria. Using growth-promoting substances, producer bacteria enhance microalgae biology activity, similar to how they have been used to promote the successful production of crops. The aim of this study was to evaluate the promoter capacity of strains Bacillus subtilis, Corynebacterium aquatile and Flavobacterium aquatile, evaluate their ability to improve the growth rate of microalgae Botryococcus braunii and to optimize the process derived from its cultivation. This study showed that the tested bacteria were able to increase up to 1.7 times the B. braunii growth rate and this promoting ability remained present in cell lysate preparations from the same bacterial strains.RESUMEN: El empleo de bacterias productoras de sustancias promotoras de crecimiento, para mejorar la e ciencia en el crecimiento de las microalgas y así potenciar su actividad en procesos industriales es una práctica que ha tomado fuerza durante los últimos años, de manera análoga a como han sido utilizadas las bacterias para favorecer la producción exitosa de cultivos vegetales. El objetivo de este trabajo fue evaluar la capacidad de las cepas Flavobacterium aquatile, Corynobacterium aquatile y Bacillus subtilis de actuar como promotoras en el crecimiento de la microalga Botryococcus braunii con el n de mejorar su velocidad de crecimiento y optimizar los procesos derivados de su cultivo. Este estudio muestra que las bacterias evaluadas tienen la capacidad de aumentar hasta 1,7 veces el crecimiento de B. braunii y esta capacidad promotora continúa presente en preparaciones de lisados celulares procedentes de estas mismas cepas bacterianas

Genome-wide identification of genes involved in growth and fermentation activity at low temperature in Saccharomyces cerevisiae

Fermentation at low temperatures is one of the most popular current winemaking practices because of its reported positive impact on the aromatic profile of wines. However, low temperature is an additional hurdle to develop Saccharomyces cerevisiae wine yeasts, which are already stressed by high osmotic pressure, low pH and poor availability of nitrogen sources in grape must. Understanding the mechanisms of adaptation of S. cerevisiae to fermentation at low temperature would help to design strategies for process management, and to select and improve wine yeast strains specifically adapted to this winemaking practice. The problem has been addressed by several approaches in recent years, including transcriptomic and other high-throughput strategies. In this work we used a genome-wide screening of S. cerevisiae diploid mutant strain collections to identify genes that potentially contribute to adaptation to low temperature fermentation conditions. Candidate genes, impaired for growth at low temperatures (12 °C and 18 °C), but not at a permissive temperature (28 °C), were deleted in an industrial homozygous genetic background, wine yeast strain FX10, in both heterozygosis and homozygosis. Some candidate genes were required for growth at low temperatures only in the laboratory yeast genetic background, but not in FX10 (namely the genes involved in aromatic amino acid biosynthesis). Other genes related to ribosome biosynthesis (SNU66 and PAP2) were required for low-temperature fermentation of synthetic must (SM) in the industrial genetic background. This result coincides with our previous findings about translation efficiency with the fitness of different wine yeast strains at low temperature.Funding from the Spanish Government trough MINECO and FEDER funds: MINECO AGL2012-32064 and AGL2015-63629-R grants, INIA RM2012-00007-00-00 grant, MINECO RTC-2014-2186-2 and MINECO PCIN-2015-143 grants is acknowledged.Peer reviewe