Price Behavior in an Inflationary Environment: Evidence from Supermarket Data

This paper analyzes several important aspects of price behavior using disaggregated weekly data on prices of supermarket products in Colombia between 1991 and 1994. The analysis shows that despite hight and persistent rates of inflation in the economy, price quotations persist on average for two months. The large proportion of observations for which stores opt not to change prices highlight the importance of menu costs, even in an economy accustomed to persistent double-digit inflation. Despite the seemingly hight levels of rigidity, the degree of real price erosion found before prices change are lower than those found in other inflationary economies. Price declines are not uncommon, and downward rigidity does not seem to be an issue in the Colombian inflationary environment. Aggregate price changes are also found to exert an important effect on relative price variation at the aggregate and commodity level.

Constructing the "good portuguese" and their enemy-others: the discourse of the far-right Chega party on social media

The election of André Ventura, leader of the Chega party, as a member of parliament in 2019 marked the history of democracy in Portugal. It was the first time that a far-right party gained political representation. Far-right political parties promote a discourse that defends the ideal of the “pure people” that is threatened by enemy-Others, and only the party can save them from the menace. The purpose of this research was to explore the social representations of the “good Portuguese” and the enemy-Others that are reproduced in Ventura's discourse on social media networks. This study integrates the Social Representations Theory and Critical Discourse Studies and focuses on the meanings and the discursive strategies used by the leader of Chega. Therefore, the 253 publications shared on his Facebook, Twitter, and Instagram accounts during the last month of the 2021 presidential campaign were analysed. It was found that Ventura refers to the “good Portuguese” as Europeans and hard workers that are threatened by two enemies. On the one hand, the Roma community, Afro-Portuguese people, and anti-fascist protesters, who are all seen as criminals and exploiters of the “pure people”. On the other hand, the traditional parties were represented as corrupt and traitors for not privileging the “good Portuguese”. In this context, Ventura appears as the strong and unstoppable hero destined to save Portugal. Based on these results, the implications of his discourse in the configuration of social representations that promote polarisation and social exclusion are discussed.A eleição de André Ventura, líder do partido Chega, como membro do parlamento em 2019 marcou a história da democracia em Portugal por ser a primeira vez que um partido da extrema- direita obteve representação política. Estes partidos promovem um discurso que defende a ideia de que uma parte da população, definido como o verdadeiro povo, está ameaçado por um Outro inimigo, e só o partido poderá salvá-lo. Assim, o propósito desta investigação foi explorar as representações sociais dos “portugueses de bem” e dos Outros-inimigos que são reproduzidas no discurso de Ventura nas redes sociais. Portanto, foram analisadas as 253 publicações feitas nas suas contas de Facebook, Twitter e Instagram durante o último mês da sua campanha presidencial em 2021. Seguindo uma integração da Teoria das Representações Sociais com a Análise Crítica do Discurso, foram analisadas as significações e estratégias discursivas utilizadas pelo líder do Chega. A análise sugere que Ventura representa os “portugueses-de- bem” como europeus e trabalhadores árduos, mas que são ameaçados por dois tipos de inimigos. Por um lado, a comunidade cigana, as pessoas com origem africana e os detratores do Chega, que são vistos como criminosos, agressivos e exploradores do verdadeiro povo. Por outro, os partidos tradicionais, representados como corruptos e traidores do povo por não privilegiar os portugueses-de-bem. Neste contexto o Ventura aparece como o forte e imparável herói destinado a salvar Portugal. Com base nesses resultados, são discutidas as implicações do seu discurso na configuração de representações sociais que promovem a polarização e a exclusão social

Pensionados por invalidez deben tener derecho a una opción laboral

Desde hace poco más de un año se está anunciando con vehemencia la necesidad de propiciar un gran debate nacional para lograr una nueva reforma pensional. Entre las razones que se aducen están la informalidad laboral y los problemas de equidad del sistema, que ponen en la cuerda floja su sostenibilidad financiera, con el punto más álgido en el año 2050. De igual forma, la posibilidad que existe de que una buena cantidad de jubilados no cuenten con un ingreso suficiente para vivir, lo cual los obligaría a buscar otros recursos o hacer que el Estado les otorgue un subsidio

Presente y futuro del derecho del trabajo: breve historia jurídica del derecho del trabajo en Colombia

El acontecimiento jurídico del siglo XX, sin duda, lo constituye el nacimiento y consolidación de una disciplina jurídica que tiene por objeto regular la relación capital-trabajo en forma autónoma. El presente escrito tiene como finalidad describir las vicisitudes del nacimiento del derecho del trabajo y los procesos que han enmarcado la evolución de esta rama del derecho así como una descripción de las tendencias que experimenta esta disciplina en el inicio del siglo XXI

Principios constitucionales y legales del derecho del trabajo colombiano

Los principios del Derecho del Trabajo constituyen el ADN de esta disciplina jurídica y la clave para resolver los problemas de interpretación y aplicación de las normas en materia laboral. Este libro tiene por objeto identificar, en los rangos constitucional y legal, esos fundamentos sobre los cuales descansa la rama del Derecho que regula la relación capital-trabajo, y determinar la naturaleza jurídica, el alcance y las aplicaciones de cada uno, para dar al lector un panorama completo sobre el tema. La Constitución Política de 1991 elevó a rango constitucional un elenco de principios que, a pesar de parecer reiterativos de los estipulados en el Código Sustantivo del Trabajo de 1950, han dado lugar al desarrollo de la jurisprudencia constitucional y han permitido actualizar las instituciones jurídico-laborales clásicas para acercarlas al modelo constitucional del Estado Social de Derecho

Production of Bio-Based Chemicals and Polymers from Renewable Feedstocks: Bioprocesses Development

Tesis por compendio[ES] El aprovechamiento de subproductos para producir biocombustibles, energía y compuestos químicos básicos es cada vez más necesario en la situación actual de escasez de petróleo y preocupación por el medioambiente. Muchos compuestos que tradicionalmente han sido producidos a partir del petróleo pueden sintetizarse hoy día de forma biotecnológica empleando recursos renovables. En este contexto, los microorganismos pueden aprovecharse eficazmente como biocatalizadores para llevar a cabo estas transformaciones. Con este tipo de procesos se pueden aprovechar residuos o materias primas renovables para la obtención de productos de interés como bioplásticos de origen microbiano o productos químicos que pueden servir como monómeros para la síntesis de plásticos biodegradables u otro tipo de aplicaciones. La contaminación ambiental causada por los residuos de polímeros sintéticos no biodegradables es un problema en aumento debido a la estabilidad de los compuestos derivados de los combustibles fósiles. En contraste, los bioplásticos pueden obtenerse de fuentes renovables, lo que posibilita el desarrollo de procesos de producción sostenible. En este trabajo de investigación se han estudiado y desarrollado bioprocesos para la producción de polihidroxialkanoatos, 2,3-butanodiol y ácido D-láctico de forma sostenible empleando materias primas renovables como el suero lácteo de quesería, aceite de camelina, glicerina, fracción orgánica de residuos urbanos y residuos de naranja. La caracterización de las materias primas de partida se realizó mediante técnicas de análisis composicional, análisis en HPLC, cromatografía de gases y técnicas espectrofotométricas. Con estos resultados se hizo una selección de cepas bacterianas capaces de sintetizar los productos de interés a partir de los sustratos seleccionados. Una vez seleccionadas las cepas, el trabajo se centró en el desarrollo de los procesos para conseguir buenos rendimientos de fermentación y su escalado. Por lo tanto, este trabajo de investigación aporta conocimientos sobre la identificación y selección de biocatalizadores industriales para el uso de materias primas renovables y residuos industriales para la producción de productos químicos y polímeros de base biológica. Estos estudios allanan el camino para el futuro desarrollo de procesos biotecnológicos sostenibles en el marco de las biorrefinerías y de la bioeconomía circular.[CA] L'aprofitament de bioproductes per produir biocombustibles, energia i compostos químics bàsics és cada vegada més necessari en la situació actual d'escassetat de petroli i preocupació pel medi ambient. Molts compostos que tradicionalment s'han produït a partir de petroli es poden sintetitzar hui en dia biotecnològicament utilitzant recursos renovables. En aquest context, els microorganismes es poden utilitzar eficaçment com a biocatalitzadors per dur a terme aquestes transformacions. Amb aquest tipus de processos es poden utilitzar residus o matèries primeres renovables per obtenir productes d'interès com bioplàstics d'origen microbià o químics que puguen servir de monòmers per a la síntesi de plàstics biodegradables o altres aplicacions. La contaminació ambiental causada per residus de polímers sintètics no biodegradables és un problema creixent a causa de l'estabilitat dels compostos de combustibles fòssils. Per contra, els bioplàstics es poden obtenir a partir de fonts renovables, permetent el desenvolupament de processos productius sostenibles. En aquest treball de recerca s'han estudiat i desenvolupat bioprocessos per a la producció de polihidroxialcanoats, 2,3-butanodiol i àcid D-làctic de manera sostenible utilitzant matèries primeres renovables com sèrum de llet, oli de camelina, glicerina, fracció orgànica de residus urbans i residus de taronges. La caracterització de matèries primeres inicials es realitza mitjançant tècniques d'anàlisi composicional, anàlisi HPLC, cromatografia de gasos i tècniques espectrofotomètriques. Amb aquests resultats es crea una selecció de soques bacterianes capaç de sintetitzar els productes d'interès dels substrats seleccionats. Una vegada seleccionades les soques, el treball es va centrar en el desenvolupament dels processos per aconseguir uns bons rendiments de fermentació i el seu escalat. Per tant, aquest treball de recerca aporta coneixements sobre la identificació i selecció de biocatalitzadors industrials per a l'ús de matèries primeres renovables i residus industrials per a la producció de productes químics i polímers de base biològica. Aquests estudis amplien el coneixement per al futur desenvolupament de processos biotecnològics sostenibles en el marc de la biorefineria i la bioeconomia circular.[EN] The use of by-products to produce biofuels, energy and basic chemicals is increasingly necessary in the current situation of oil shortages and environmental concern. Many compounds that have traditionally been produced from oil can now be synthesised in a biotechnological way using renewable resources. In this context, microorganisms can be effectively used as biocatalysts to carry out these transformations. With this type of process, waste streams or renewable raw materials can be used to obtain products of interest such as bioplastics of microbial origin or chemical products that can serve as monomers for the synthesis of biodegradable plastics or other types of applications. Environmental pollution caused by non-biodegradable synthetic polymer waste is a growing problem due to the stability of compounds derived from fossil fuels. In contrast, bioplastics can be obtained from renewable sources, which enables the development of sustainable production processes. In this research work, bioprocesses for the production of polyhydroxyalkanoates, 2,3-butanediol and D-lactic acid using renewable raw materials such as cheese whey, camelina oil, glycerine, organic waste and orange waste were studied and developed. The characterisation of the raw materials was carried out using compositional analysis, HPLC analysis, gas chromatography and spectrophotometric techniques, among others. With these results, a selection of bacterial strains capable of synthesising the products of interest from the selected substrates was made. Once the strains were selected, the work was focused on process development in order to optimize fermentation yields and scale-up. Therefore, this research work provides knowledge on the identification and selection of industrial biocatalysts for the use of renewable feedstocks and industrial wastes for the production of bio-based chemicals and polymers. These studies pave the way for further development of sustainable biotechnological processes in the framework of biorefineries and circular bioeconomy.Bustamante Jaramillo, DA. (2021). Production of Bio-Based Chemicals and Polymers from Renewable Feedstocks: Bioprocesses Development [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/175819TESISCompendi

Plasma-assisted liquid phase epitaxy of gallium nitride using molten gallium.

Next generation semiconductor materials such as Gallium Nitride (GaN) and Silicon Carbide (SiC) are rapidly replacing Silicon (Si) for high power and high frequency applications due to Si’s inherent limitations. Despite the advantages of GaN over SiC, adoption of GaN has been hindered due to the lack of a cost-effective bulk production technique. Thus, the inability to precure native substrates requires GaN-based architectures to be heteroepitaxially synthesized on non-native substrates, such as sapphire and even SiC. This research seeks to develop a cost effective and scalable method to produce low defect, bulk GaN encouraging the adoption of GaN based devices which ultimately will allow reduction of energy losses in the grid. Specifically, two conceptual methods for the growth of bulk GaN will be explored. The first one is a film-based method, which is based on self-oriented growth of GaN films on a melt gallium layer. In this process, a highly oriented GaN film, made by exposing Ga to plasma-activated nitrogen atoms, is epitaxially thickened into a millimeter-thick GaN film via metalorganic chemical vapor deposition (MOCVD) or halide vapor phase epitaxy (HVPE). The second proposed concept is a crystal-based method. In this process, single crystalline GaN crystals are obtained by nucleation of GaN out of a Ga melt when exposed to nitrogen plasma. Later, those crystals are enlarged via plasma-assisted liquid phase epitaxy. As a first step to develop a plasma-assisted liquid phase epitaxy technique the wetting properties of Ga, as well as the interaction between molten Ga and plasma were studied. It was found that both an increment in temperature and the addition of other elements can improve the wettability of Ga by reducing the surface tension of the molten metal. However, these variables were not as effective as the dissolution of nitrogen radicals into the melt. Absorption/desorption experiments indicated a rapid adsorption/dissolution of the gas into the molten metal when gallium was exposed to plasma. The overall interaction between Ga and plasmas is composed of five processes: (1) surface adsorption, (2) diffusion into the bulk, (3) recombination inside the bulk, (4) surface recombination, and (5) desorption of species from the bulk. The concentration of radicals inside the metal is determined by the rate in which each process is completed. The self-oriented growth of GaN crystals on molten Ga was found to be dependent of the ability of Ga to spread. XRD characterization showed that flat GaN films only presented reflections of the (0002) and (0004) planes of the hexagonal GaN, whereas the non-flattened GaN films showed the presence of all the characteristic planes of the wurtzite GaN. On the other hand, micron-sized wurtzite and zincblende GaN crystals were obtained by exposing a mixture of Ga and LiCl to nitrogen plasma. It is believed that GaN crystals crystalized from a Li-Ga-N melt that was formed by the interaction between Li3N, Li and Ga. In a typical plasma nitridation experiment, spontaneous nucleation of GaN out of molten Ga leads to the formation of a thick GaN crust on top of the surface of the metal. Similarly, the regrowth experiments using GaN seeds or GaN-on-sapphire substrates failed because of such spontaneous nucleation. The formation of the GaN crust can be explained by the spinodal decomposition mechanism when the concentration of nitrogen inside the Ga reaches a limit. To control the concentration of nitrogen inside the melt, a unique concept of pulsed plasma was introduced. Results showed that pulsed plasma-assisted liquid phase epitaxy allowed a delay in spontaneous nucleation while promoting the growth of additional layers on the pre-existing seeds. A mass transport model was developed to discuss the effect of bulk recombination, diffusion, and pulsing in the concentration of nitrogen into the molten Ga. Results indicated that in the pulsing experiments both the recombination of radicals in the bulk and the diffusion of species into the metal are favored compared to the dissolution of radicals. As a result, the concentration of nitrogen at the surface of the metal is decreased, while the concentration of nitrogen at the surface of the substrate is increased. The results presented in this work provide insights into low-pressure, metastable crystal growth processes that include both nitrogen dissolution and crystallization of GaN out of a Ga melt. Specifically, the roles of plasma and alkali or semi alkali metals in the dissolution of nitrogen into Ga and the understanding of the mechanism in which GaN crystals nucleate are elucidated. Furthermore, the results obtained in this work could be extended to several other compound semiconductor systems that decompose before melting and are unsuitable for traditional crystal growth techniques