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O objetivo deste estudo era determinar a incidência de hidatidose suína em suínos abatidos na área costeira. Utilizamos 300 porcos de vários cantões próximos, selecionando 12 porcos por dia, através de inspeção diária no momento do abate. A presença de cistos, a razão do estudo e as lesões causadas por eles foram identificadas macroscopicamente. As vísceras foram inspecionadas: fígados, pulmões e rins, onde o parasita tem o maior apetite para produzir a doença. A inspeção foi realizada primeiro visualmente e depois os órgãos afetados pelos quistos, o motivo do estudo, foram apreendidos e levados ao laboratório em caixas refrigeradas para continuar com o estudo microscópico. Foram realizados testes de laboratório utilizando o método analítico para determinar a presença de ovos parasitas e sua fertilidade. Durante a avaliação dos dados, o Método Percentual foi aplicado para determinar em porcentagem quantos casos são positivos ou negativos em hidatidoses em suínos. Foram avaliadas as seguintes variáveis: seleção de animais inspecionados post-mortem de diferentes idades, raças, sexo, porcentagem de porcos positivos para cistos hidatidos, origem dos porcos positivos para cistos hidatidos e determinação da fertilidade dos cistos. Através da análise dos resultados foi determinado que há uma incidência de 5,7% de hidatidose em suínos abatidos no matadouro municipal de Babahoyo Canton; uma maior incidência de cistos hidatidos foi encontrada em fêmeas 3,7%, sem que isso signifique que o sexo seja determinante na presença da doença; uma maior incidência foi observada em suínos crioulos 13. 8%, embora eu não acredite que as raças sejam um determinante na incidência da doença, mas as condições de manejo na produção de suínos; o órgão de maior preferência pelo parasita são os rins que encontram 82,4% de incidência; a fertilidade dos cistos hidatidos encontrados foi de 41,2%, o que significa que se eles forem ingeridos por um hospedeiro intermediário eles têm um alto risco de transmissão da doença.

O objetivo desta pesquisa era determinar a freqüência de fêmeas bovinas grávidas no abate e sua incidência na produção animal. O estudo foi realizado na cidade de Ventanas, Província de Los Rios. A fórmula foi aplicada para calcular o tamanho da amostra correspondente a uma população específica e foi determinada uma amostragem de 357 casos. A metodologia utilizada no exame post-mortem determinou as fêmeas em gestação e também calculou a idade, local de origem e data da amostragem. Uma vez abatidas as fêmeas, o útero foi separado da carcaça para ser examinado fora da carcaça, que foi aberta com uma tesoura, separando as membranas fetais e procedendo à extração do feto, para calcular a idade aproximada do feto, usando um gráfico de crescimento RICTER E GOETZE. Além disso, todas as informações acima mencionadas foram registradas em tabelas preparadas para este fim. Para a presente investigação, foi aplicado o método percentual. Foram avaliadas as seguintes variáveis: Percentual de fêmeas grávidas abatidas, tempo e idade de gestação, raça e origem das fêmeas abatidas. Os resultados obtidos com os 357 casos amostrados, 159 vacas prenhas foram encontradas no abatedouro municipal a serem abatidas, o que representou 44,5%, e 198 vacas foram encontradas vazias (55,5%), a análise de sensibilidade determinou que havia significância estatística. De acordo com o tempo de gestação das vacas prenhes encontradas para abate no abatedouro Municipal da cidade de Ventanas, na faixa de 0-3 meses foram encontrados 64 casos (40,3%), na faixa de 3-6 meses foram detectados 83 casos (52,2%), esta é a faixa com maior número de vacas prenhes e na faixa de 6-9 meses foram encontradas 12 vacas prenhes (7,5%), a análise do quadrado Chi mostrou que há significância estatística. De acordo com a origem das vacas encontradas prenhas que foram abatidas no abatedouro municipal da cidade de Ventanas, foi encontrado o seguinte Em Moraspungo foram encontrados 29 casos (18,24%), em San Luis foram detectados 15 casos (9,43%), em Caluma e Pueblo Viejo o número de vacas prenhas foi de 13 respectivamente (8,18%). A análise qui-quadrada mostrou significância estatística. Dos 173 casos amostrados, 47,8% correspondiam à raça Brahman. Dos 127 casos amostrados, a raça cruzada representou 35,2%, seguida pelas raças Jersey, Charolais e Holstein. A análise qui-quadrada mostrou significância estatística.

Zearalenone (ZEA), a mycotoxin recognized with estrogenic effects, has a contaminant prevalence in corn, sorghum and wheat, mainly being produced by fungi: Fusarium graminearum, and other species such as culmorum and tricintum. Zearalenone effects are estrogenic. Being swine one of the most sensitive animals. Gilts often present hyperestrogenism and manifest as vulvovaginitis and mammary glands enlargement. The objective of this study was to assess ZEA toxic effects in gilts, during 52 days period, consuming naturally contaminated feed, using 1200 ppb levels (ZEA) and verify two commercial toxin binders efficiency to reduce their potential detrimental effects. 24 recently weaned gilts were selected; first seven days were for adaptation, then each gilt was assigned within one of the four experimental groups identified as: 1) control diet without ZEA, 2) positive control diet with 1,200 ppb of ZEA, 3) challenge diet with 1,200 ppb of ZEA and 1.5 kg / t of organoaluminosilicate, 4) challenge diet with 1,200 ppb of ZEA and 1.5 kg / t of Aluminosilicate + yeast cell walls. The obtained information was analyzed through the statistical software SYSTAT, by the Tukey test where the difference of means was defined. The significance value was based on a p < 0.05. There were statistically significant differences in reproductive tract weight and length, vulva volume and cervix width between treatments.

La pandemia del COVID-19 ha puesto en evidencia el grave problema de la falta de colaboración entre las entidades y los contratistas en la ejecución de los contratos con el Estado. Ante situaciones imprevisibles y la necesidad de toma de decisiones ágiles para mitigar o disminuir los impactos de la pandemia, en muchos casos las partes mantuvieron una conducta conflictiva antes que una colaborativa que priorice la buena gestión contractual para alcanzar la finalidad de la contratación, lo cual puso en riesgo la atención de necesidades para atender la emergencia sanitaria, el dinamismo de la economía, la generación de puestos de trabajo, la inversión en gasto público, entre otros fines. Por ello, es importante conocer las herramientas de colaboración en contratación pública que están disponibles en la normativa vigente, así como aquellas que pueden ser implementadas, sin perder de vista que fomentar la confianza entre los actores del sistema de contratación pública resulta esencial para alinear los intereses de las partes y generar una efectiva gestión colaborativa. En el presente artículo se analizarán principales conceptos sobre la colaboración entre las partes y la forma en que diferentes herramientas pueden fomentar esta colaboración.

espanolEn el ano 2019 se llevaron a cabo en Lima los XVIII Juegos Panamericanos y Sextos Juegos Parapanamericanos. Este fue el mayor evento deportivo multidisciplinario organizado por el Peru. Este evento fue un gran reto para el Peru, tanto por su complejidad como por el corto tiempo con el que se contaba para su ejecucion. Para cumplir sus objetivos, el Proyecto Especial a cargo de la organizacion de los Juegos empleo diferentes mecanismos de contratacion y herramientas de gestion novedosos, dentro del marco de un contrato de Gobierno a Gobierno con el Reino Unido. En este contexto, estas experiencias han sido replicadas en un nuevo Modelo de Ejecucion de Inversiones Publicas que puede ser empleado por los Proyectos Especiales de Inversion Publica. Lo que se busca mediante este nuevo esquema es destrabar las inversiones publicas, gestionandolas y ejecutandolas eficientemente, empleando altos estandares internacionales.La regulacion de estos Proyectos Especiales de Inversion Publica se ha venido desarrollando progresivamente en el ultimo ano, incorporando incluso la posibilidad de celebrar contratos de Gobierno a Gobierno. A la fecha, se encuentra en operacion el Proyecto de Inversion Publica, denominado “Escuelas Bicentenario”, que permitira analizar el funcionamiento de este nuevo Modelo de Ejecucion de Inversiones Publicas. Actualmente, en medio de constantes anuncios de modificacion de la Ley de Contrataciones del Estado, se ha puesto sobre la mesa la discusion de la oportunidad y pertinencia de implementar varias de las herramientas del Modelo de Ejecucion de Inversiones en la normativa de contrataciones del Estado, a efectos de mejorar la ejecucion de las obras publicas. En este escenario, es importante conocer estas herramientas comprendidas en el Modelo de Ejecucion de Inversiones Publicas como punto de partida para evaluar posibles propuestas de mejora a la normativa de contrataciones del Estado, ya sea para prever nuevas figuras o para mejorar la regulacion existente. Para dicho fin, en el presente articulo se resenan algunas de las principales herramientas del Modelo de Ejecucion de Inversiones Publicas, asi como los beneficios que estas podrian aportar para la ejecucion de las obras publicas. EnglishAfter the XVIII Pan American Games and Sixth Parapan American Games were held between July and September 2019, the largest sporting event organized and executed by Peru, which involved the deployment of novel contracting and management mechanisms, the Government has sought replicate this experience in a new investment management model. In this context, the Special Public Investment Projects were created, with the aim of applying this new investment management model for the execution of public investment projects, a package of projects or a portfolio of projects.The regulation of these Special Public Investment Projects has been progressively developed in the last year, adopting even the mechanism of Government-to-Government contracts. This regulatory development has led to the creation of the first Public Investment Project, “Escuelas Bicentenario”. With the constant announcements of modification of the Government Procurement Law, the discussion of the opportunity and relevance of implementing the tools enabled for Special Public Investment Projects in the general regulation of public contracts has been raised, in order to improve the execution of public works. In this scenario, it is important to study the tools considered in the investment execution model envisaged in Emergency Decree 021-2020, as a starting point to evaluate the proposals for improvement to the Government Procurement Law. In this article the main tools of the Investment Execution Model are reviewed, as well as the benefits these tools provide for the execution of important infrastructure projects in Peru.

The Covid‐19 pandemia has many other undesirable consequences apart of virus infection. Less people is hospitalized due to acute coronary syndrome and the delay to seek medical attention has increased. Patients with ST segment elevation myocardial infarction arrive at the hospital too late to be timely treated and we have recently seen mechanical complications that were more frequent in the past decades before the use of reperfusion strategies. In this report we describe the presentation, evolution and detailed imaging evaluation of two patients with unusual presentations of cardiac rupture: left ventricular pseudoaneurysm and left ventricular intramyocardial dissecting hematoma.

Politische Werbung in sozialen Netzwerken spielt eine immer größere Rolle: Durch die Auswertung und Analyse der in sozialen Netzwerken befindlichen, personenbeziehbaren Nutzerdaten (dem sog. Microtargeting) lassen sich individualisierte Werbebotschaften und Anzeigen erstellen, die auf unterschiedlichste Nutzergruppen zugeschnitten werden können. Während in den USA Microtargeting bereits seit geraumer Zeit von Politikern und Parteien in Wahlkämpfen eingesetzt wird, steht Deutschland bei dieser Entwicklung erst am Anfang. Neben Parteien und Politikern vertreten jedoch auch andere Institutionen, Organisationen und Nutzer politische oder gesellschaftlich relevante Standpunkte und bewerben diese in sozialen Netzwerken. Hinsichtlich bezahlter Werbeanzeigen sind in Deutschland die Gewerkschaften und die Arbeitgeberverbände kontinuierlich aktiv. Daher stellt sich die Frage, ob sich bei der politischen Werbung dieser Organisationen bereits Hinweise für ein Nutzertargeting finden lassen? Auf Basis unserer Daten aus der Facebook Ad Library soll im Artikel dieser Frage nachgegangen werden. Mit seiner Ad Library sammelt und veröffentlicht das Unternehmen Facebook seit 2019 nach eigenen Angaben alle politisch und gesellschaftlich relevanten Werbeanzeigen, für die Werbetreibende bezahlt haben. Vor diesem Hintergrund werden die unterschiedlichen Werbestrategien der deutschen Gewerkschaften und Arbeitgeberverbände im ersten Teil des Artikels anhand der Anzeigenanzahl, der Werbekosten und der Reichweite der bezahlten Werbung innerhalb des Beobachtungszeitraums März 2019 bis Juni 2020 verglichen. Im zweiten Teil wird versucht, mögliche Targeting-Strategien anhand der demographischen und der räumlichen Verteilung der Facebook - Nutzern nachzuzeichnen, denen die Werbung angezeigt worden ist.

espanolEn este informe de investigacion se presenta una experiencia de uso de situaciones adidacticas conforme al fundamento teorico de las Situaciones Didacticas de Guy Brousseau y la teoria de los campos conceptuales de Vergnaud, referentes que se usaron en el analisis de la indagacion respecto de la conceptualizacion de los numeros negativos, en una estudiante de cuarto ano de Ensenanza Basica en una escuela de Valparaiso-Chile. Usando como recurso el entorno de Scratch, se crearon situaciones, con la intencion de que la estudiante extendiera su conceptualizacion respecto de estos numeros y sin tener conocimientos previos de los aspectos formales de estos. Como resultado de ello, se evidencio que la estudiante extendio su conceptualizacion. Es una investigacion cualitativa, en la que se utilizaron como instrumentos la entrevista y el registro de las producciones escritas de la estudiante para realizar el analisis, mediante este proceso ha sido posible reconocer las condiciones en las que se alcanza la extension numerica para el caso estudiado, las cuales son: reconocimiento de los distintos niveles de conceptualizacion de los numeros negativos, dualidad del signo menos y aceptacion de la sustraccion de enteros, y explorar las dificultades que tuvo para aprender conceptos de numeros negativos. EnglishThis research report presents an experience of the use of non-didactic situations according to the theoretical foundation of Guy Brousseau’s Didactic Situations and Vergnaud’s theory of conceptual fields, theoretical references that were used in the analysis of inquiry regarding conceptualization of the negative numbers, in a fourth year student of Basic Education in a school in Valparaiso-Chile. Using the Scratch environment as a resource, situations were created, with the intention that the student extends her conceptualization regarding these numbers and without prior knowledge of the formal aspects of these. As a result, it was evident that the student extended his conceptualization. It is a qualitative investigation, which used as instruments the interview and the recording of the student’s written productions to carry out the analysis, through this process it has been possible to recognize the conditions in which the numerical extension is reached for the case studied, which They are: recognition of the different levels of conceptualization of negative numbers, duality of the minus sign and acceptance of integer subtraction, and exploring the difficulties he had in learning concepts of negative numbers.

Contemporary political communication is a multi- and cross-platform process. Because of its complexity, new tools are necessary to monitor and understand it. We present a system that ingests, stores, and processes political data from Twitter, Facebook, and online news articles. We visualize the data in the form of a freely accessible online dashboard. The political dashboard (https://political-dashboard.com/) aims to provide online political transparency and assist researchers, journalists, and the general public in understanding the German online political landscape.

Gold nanoparticles dispersed on MnOx/TiO2 were used to perform the oxidation of carbon monoxide at low temperatures. Remarkable dispersion of gold nanoparticles under hydrogen treatment was obtained, mainly in Au–MnOx/TiO2 catalysts with 2 wt% Au and 5 wt% Mn, where the Au nanoparticles displayed average sizes of 1–3 nm. The addition of Au nanoparticles to the MnOx/TiO2 catalysts promoted both the CO oxidation from 0 °C and stability at room temperature. This behavior could be attributed to the synergistic interactions between Au0/Au1+ and Mn3+/Mn4+ on the Au–MnOx/TiO2 catalyst surface.

Desde la recesión financiera del 2007-2009 y hasta el día de hoy, los principales bancos centrales han utilizado a instrumentos de política no tradicionales para estimular la actividad económica. Un ejemplo muy característico fue la expansión de sus hojas de balance a través de la compra de títulos de deuda gubernamental de largo plazo. En este artículo analizo el efecto de esta herramienta “no convencional” en los mercados de crédito y lo comparo con aquel de instrumentos convencionales tales como las operaciones de mercado abierto. Nuestros resultados sugieren que las compras de títulos de deuda gubernamental de largo plazo estimulan la actividad en los mercados de crédito y reducen los costos de financiamiento tanto privado como público sólo cuando existe un régimen con tasas de interés bajas y deuda fiscal limitada. De otra manera, esta política incrementa el costo del servicio a la deuda, lo que resulta en una contracción del crédito. Por otro lado, las operaciones de mercado abierto facilitan la disponibilidad de crédito pero afectan negativamente la compartición del riesgo en la economía.

A novel approach is presented to determine four bisphenols in water and urine samples, employing magnetic dispersive solid‐phase extraction combined with liquid chromatography and diode array detection. A modified zeolite‐based magnetic composite was used as an efficient sorbent, combining the advantages of magnetic materials with the remarkable properties of zeolites. A multivariate optimization design was employed to optimize some experimental factors affecting magnetic dispersive solid‐phase extraction. The method was evaluated under optimized conditions (i.e., amount of sorbent, 50 mg; sample pH, unadjusted; NaCl concentration, 1.25%; extraction and elution time, 2 min; eluent solvent, ethanol; eluent solvent volume, 400 µL), obtaining good linearity with correlation coefficients ranging between 0.995 and 0.999 (N = 5) (from 2 to 250 µg/L for bisphenol A, bisphenol AP, and bisphenol P and from 5 to 250 µg/L for bisphenol AF). Method repeatability was assessed obtaining coefficients of variation between 3 and 11% (n = 6). Finally, the method was applied to spiked real samples, obtaining for water samples relative recoveries between 83 and 105%, and for urine samples between 81 and 108% for bisphenol A, bisphenol AP, and bisphenol AF, and between 47 and 59% for bisphenol P. The authors would like to thank the Spanish Ministry of Economy and Competitiveness and European Union (FEDER funds) (project no. CTQ2016-79991-R) and Generalitat Valenciana (Spain) (project no. PROMETEO/2018/087) for the financial support. P. Baile also thanks Ministry of Education, Culture and Sports for her FPU grant (FPU14/04589).

Este artículo muestra la importancia de la MML y la aplicación que de esta metodología realizan los semilleros de investigación en la zona centro sur -ZCSUR de una Universidad a distancia. La investigación realiza el inventario de todos los semilleros de la Universidad en la zona, determina cada uno de los aspectos teóricos de la MML e indaga por medio de una encuesta realizada a los 30 semilleros de la zona Centro Sur, sobre diferentes metodología y técnicas que guían el trabajo del semillero, tomando como referente la matriz de marco lógico (MML). Se encontró que es deficiente el desempeño de los semilleros en la utilización de metodologías como la MML y se realiza un comparativo entre lo que se hace o lo que debe hacerse resaltando las ventajas que trae la aplicación de la metodología para el incremento en la producción y efectividad de los semilleros de investigación.

Introduction. The roles of angiotensin II (Ang II) in the brain are still under investigation. In this study, we investigated if Ang II influences differentiation of human neuroblastoma cells with simultaneous activation of NADPH oxidase and reactive oxygen species (ROS). Moreover, we investigated the Ang II receptor type involved during differentiation. Methods. Human neuroblastoma cells (SH-SY5Y; 5 × 10 5 cells) were exposed to Ang II (600 nM) for 24 h. Differentiation was monitored by measuring MAP2 and NF-H levels. Cell size and ROS were analyzed by flow cytometry, and NADPH oxidase activation was assayed using apocynin (500 μM). Ang II receptors (ATR) activation was assayed using ATR blockers or Ang II metabolism inhibitors (10-7 M). Results. (1) Cell size decreased significantly in Ang II-treated cells; (2) MAP2 and ROS increased significantly in Ang II-treated cells with no changes in viability; (3) MAP2 and ROS decreased significantly in cells incubated with Ang II plus apocynin. (4) A significant decrease in MAP2 was observed in cells exposed to Ang II plus PD123.319 (AT2R blocker). Conclusion. Our findings suggest that Ang II influences differentiation of SH-SY5Y by increasing MAP2 through the AT2R. The increase in MAP2 and ROS were also mediated through NADPH oxidase with no cell death.

The Webquest is a type of didactic activity based on constructivist assumptions of the teaching - learning process. This research, in the context of innovation, proposes a didactic experience for three groups of teachers, to design, develop and implement webquest for the teaching of science. It is guided by a guided indagatory methodology that promotes meaningful learning and improves academic performance. The methodological teaching proposal is theoretically based on the significant learning of Ausubel, on cognitive developments of Piaget, zone of proximal development of Vygotsky and the cooperative work of Jonhson and Jonhson. The research is experimental, essentially quantitative, with an exploratory, descriptive study. The results ensure an important advance between the pretest and posttest of each work group, with a tangible product that can be used in the science classrooms.

This study investigates the possibilities and limits presented by the newly created ad libraries from Facebook and Google to analyze online political campaigns. We selected Germany as a case study and focused on the months leading up to the 2019 elections to the European Parliament. We identified the political actors that were active advertisers, compared their spending, and contrasted the number of ad impressions with user engagement on their organic online content. From the political ads, we extracted the unique ads and manually analyzed a subsample of them. Furthermore, we explored regional and demographic distributions of users reached by the advertisements and used them as a proxy for the advertisers’ targeting strategies. We also compared the success of the ad campaigns on boosted Facebook posts. We found that even though all the major German political parties engaged in online ad campaigns, they kept their attempts at microtargeting to a minimum. Although their Facebook-sponsored posts were more successful than normal posts, we did not find statistical significance for all the political parties. Interestingly, we noticed that the distribution of users reached by the right-wing party Alternative fur Deutschland (AfD) diverges from that of the other parties. Finally, we discuss further challenges for enhancing transparency in online advertising.

Within the main contracting mechanisms used by the Special Project in chargeof the organization and development of the X VIII Pan American Games and VI ParapanAmerican Games of 2019 for the acquisition of complex and sophisticated goods, servicesand infrastructure, considering the lack of national experience in mega sport events,we can find Government-to-Government Agreements and New Engineering Contracts.Considering the results of these contracting mechanisms, there are many public entitiesevaluating the possibility to use them to carry out their own projects. However, it is notunusual for these entities to not fully understand the scope and nature of said mechanisms.Therefore, this paper explains the main characteristics of these two contractual figures, aswell as the experience of their use in the Pan American Games, in order to appoint some considerations that public entities must take into account before deciding to use them. Entre los principales mecanismos de contratación empleados por el Proyecto Especial a cargo de la preparación y desarrollo de los Juegos Panamericanos del 2019 para abastecerse de bienes, servicios y obras complejos de manera oportuna y eficiente, considerando la falta de experiencia nacional en las contrataciones necesarias para mega eventos deportivos, se encuentran el Acuerdo de Gobierno a Gobierno y el empleo de los contratos NEC 3 - Opción F. En vista de los resultados que viene obteniendo el Proyecto Especial con el empleo de estas figuras, no son pocas las entidades que se encuentran explorando la posibilidad de utilizarlas para llevar a cabo sus propios proyectos; aunque muchas veces sin terminar de comprender el alcance y naturaleza de estos mecanismos. Por ello, en el presente artículo se desarrollan las principales características de estas dos herramientas de contratación, así como la experiencia de su empleo en los Juegos Panamericanos, a fin de concluir en algunas consideraciones que deben tomar en cuenta las entidades antes de replicar dicho esquema.

Politische Debatten werden in Deutschland zunehmend uber soziale Medien gefuhrt. Die dabei produzierten Daten konnen mit geeigneten ,,machine learning“-Verfahren fur politisches Microtargeting genutzt werden. Die Anwendung von maschinellem Lernen auf diesen Daten ermoglicht das Zusammenfassen von Nutzern mit ahnlichem Verhalten oder Praferenzen. Dadurch konnen Gruppen identifiziert werden, die fur bestimmte politische Inhalte besonders interessant sind. In den USA werden diese Verfahren bereits intensiv genutzt. Allerdings verfugen die dortigen politischen Akteure uber Zugriff auf detaillierte Informationen uber die Wahler. Solche Daten stehen in Deutschland nicht zur Verfugung, da die deutschen Datenschutzrichtlinien deren Sammlung, Verarbeitung und Auswertung verbieten. Im folgenden Artikel zeigen wir, wie es im Einklang mit den deutschen Datenschutzgesetzen moglich ist, Daten aus dem sozialen Netzwerk Facebook zu extrahieren und damit Microtargeting zu betreiben. Vor diesem Hintergrund werden abschliesend die ethischen und politischen Konsequenzen fur das politische System diskutiert.

Community-based educational spaces (CBES; afterschool programs, community-based youth organizations, etc.) have a long history of interrupting patterns of educational inequity and continue to do so under the current educational policy climate. The current climate of education, marked by neoliberal education restructuring, has left community-based educational spaces vulnerable in many of the same ways as public schools. Considering the current political moment of deep insecurity within public education, this review of research illuminates the role community-based educational spaces have played in resisting forms of educational inequality and their role in the lives of minoritized youth. With a review of seminal education research on community-based spaces, we intend to capture the ways these diverse out-of-school spaces inform the educational experiences, political identity development, and organizing and activist lives of minoritized youth. Further, this piece contends that reimagining education beyond the borders of the school is a form of resistance, as community-based leaders, youth workers, and youth themselves negotiate the dialectical nature of community-based educational spaces within a capitalist and racialized neoliberal state.

Word embeddings are a widely used set of natural language processing techniques that map words to vectors of real numbers. These vectors are used to improve the quality of generative and predictive models. Recent studies demonstrate that word embeddings contain and amplify biases present in data, such as stereotypes and prejudice. In this study, we provide a complete overview of bias in word embeddings. We develop a new technique for bias detection for gendered languages and use it to compare bias in embeddings trained on Wikipedia and on political social media data. We investigate bias diffusion and prove that existing biases are transferred to further machine learning models. We test two techniques for bias mitigation and show that the generally proposed methodology for debiasing models at the embeddings level is insufficient. Finally, we employ biased word embeddings and illustrate that they can be used for the detection of similar biases in new data. Given that word embeddings are widely used by commercial companies, we discuss the challenges and required actions towards fair algorithmic implementations and applications.

In this work, complex weighted bipartite social networks are developed to efficiently analyze, project and extract network knowledge. Specifically, to assess the overall ease of communication between the different network sub-clusters, a proper projection and measurement method is developed in which the defined measurement is a function of the network structure and preserves maximum relevant information. Using simulations, it is shown how the introduced measurement correlates with the concept of political polarization, after which the proposed method is applied to Facebook networks to demonstrate its ability to capture the polarization dynamics over time. The method successfully captured the increasing political polarization between the Alternative fur Deutschland's (AfD) supporters and the supporters of other political parties, which is in line with previous studies on the rise of the AfD in Germany's political sphere.

In 2017, a far-right party entered the German parliament for the first time in over half a century. The Alternative fur Deutschland (AfD) became the third largest party in the government. Its campaign focused on Euroscepticism and a nativist stance against immigration. The AfD used all available social media channels to spread this message. This paper seeks to understand the AfD's social media strategy over the last years on the full gamut of social media platforms and to verify the effectiveness of the party's online messaging strategy. For this purpose, we collected data related to Germany's main political parties from Facebook, Twitter, YouTube, and Instagram. This data was subjected to a unified multi-platform analysis, which relies on four measures: party engagement, user engagement, message spread, and acceptance. This analysis proves the AfD's superior online popularity relative to the rest of Germany's political parties. The evidence also indicates that automated accounts contributed to this online superiority. Finally, we demonstrate that as part of its social media strategy, the AfD avoided discussion of its economic proposals and instead focused on pushing its anti-immigration agenda to gain popularity.

Online Social Networks (OSNs) are used increasingly for political purposes. Among others, politicians externalize their views on issues, and users respond to them, initiating political discussions. Part of the discussions are shaped by hyperactive users. These are users that are over-proportionally active in relation to the mean. In this paper, we define the hyperactive user on the social media platform Facebook, both theoretically and mathematically. We apply a geometric topic modelling algorithm (GTM) on German political parties' posts and user comments to identify the topics discussed. We prove that hyperactive users have a significant role in the political discourse: They become opinion leaders, as well as set the content of discussions, thus creating an alternate picture of the public opinion. Given that, we discuss the dangers of replicating the specific bias by statistical and deep learning algorithms, which are used widely for recommendation systems and the profiling of OSN users.

Resumen. Introducción: la implementación de la neuroimagen funcional en el estudio de diferentes patologías neurológicas y psiquiátricas permitió que se usaran como técnicas en el estudio de los trastornos relacionados con sustancias. Esta investigación tomó herramientas de la medicina nuclear con el fin de aportar al diagnóstico de personas con dependencia a sustancias psicoactivas ilegales. Materiales y métodos: se realizó un estudio descriptivo y transversal de ocho casos de pacientes entre 18 y 44 años con diagnóstico clínico conocido de trastorno por dependencia a múltiples sustancias psicoactivas, de acuerdo con los criterios diagnósticos del dsm iv-tr, que utilizaron el servicio de consulta externa de la Clínica San Miguel Arcángel, en Cartago, Colombia, durante el 2011. Se implementó el procedimiento Gammagrafía spect de perfusión cerebral con trodat - 99mTc, y se confirmó la presencia de diferentes tóxicos en orina a través del método multi drug. Resultados: se encontró en los estudios realizados con gammagrafía spect de perfusión cerebral con trodat - 99mTc disminución en la captación del radio-fármaco en los núcleos de la base de manera bilateral y asimétrica, con mayor compromiso del putamen, comparado con estudios realizados en individuos sanos. Conclusión: los hallazgos en estapoblación de pacientes con dependencia a sustancias evidenció hipocaptación en los núcleos de la base mediante la implementación de gammagrafía spect de perfusión cerebral con trodat - 99mTc, lo cual sugiere que esta metodología podría aportar argumentos técnico-científicos para realizar diagnósticos positivos o negativos sobre adicción a sustancias.

The comorbidity of depression and fibromyalgia chronic syndrome has been well documented in the literature; however, the cognitive structure of these patients has not been assessed. Previous results reported variability in cognitive rigidity in depressive patients, the key for this might be the presence of chronic physical pain such as fibromyalgia. The present study explores and compares the cognitive rigidity and differentiation, between patients with depression with and without fibromyalgia syndrome.Thirty one patients with depression and fibromyalgia were matched, considering age, sex and number of depressive episodes, with 31 patients with depression but without fibromyalgia diagnosis. Cognitive rigidity and differentiation were measured with the repertory grid technique.The results indicated that depressed patients with fibromyalgia presented higher levels of depressive symptoms, greater cognitive rigidity and lower cognitive differentiation than those without fibromyalgia.The results might inform future treatments to address the cognitive structure of these patients.La comorbilidad de la depresión y la fibromialgia ha sido bien documentada en la literatura. Sin embargo, la estructura cognitiva de estos pacientes no ha sido evaluada. Estudios previos muestran variabilidad en medidas de rigidez cognitiva en pacientes con depresión. Los síndromes físicos crónicos podrían ser una variable clave para explicar esta variabilidad presente en estudios previos. El presente estudio explora y compara la rigidez y la diferenciación cognitiva entre paciente con depresión que tienen y aquellos que no tienen fibromialgia.Treinta y un pacientes con depresión y fibromialgia fueron emparejados, considerando edad, sexo y números de episodios depresivos con 31 pacientes con depresión, pero sin diagnóstico de fibromialgia.Los resultados indican que los pacientes que presentan depresión y fibromialgia evidencian niveles más altos de síntomas depresivos, mayor rigidez cognitiva y menor diferenciación cognitiva que los pacientes sin fibromialgia.Estos resultados podrían ser considerados al momento de crear tratamientos ajustados a la estructura cognitiva de estos pacientes.

This report presents thorough research on social media platforms during the months before the 2017 German federal election. The focus is on Facebook and Twitter given their increasing role in online political communication. Over 350 million tweets and 37 thousand Facebook posts related to German politics were collected and analyzed. This work takes an overlook at the online interaction between users and political parties. Moreover, it tries to identify disinformation and manipulation techniques.

We study the effects of money growth in a neoclassical growth model with wealth effects. As the capital stock is the only component of wealth which contributes to an individual’s utility, the model should be interpreted as a model of housing production and housing wealth since the capital stock affects utility. Consistent with empirical evidence on the relationship between residential investment and GDP across countries, there are significant non-linearities between housing market activity and aggregate income in our framework

We examined the properties of the nanocomposite γ-Fe

A segment of the political discussions on Online Social Networks (OSNs) is shaped by hyperactive users. These are users that are over-proportionally active in relation to the mean. By applying a geometric topic modeling algorithm (GTM) on German users’ political comments and parties’ posts and by analyzing commenting and liking activities, we quantitatively demonstrate that hyperactive users have a significant role in the political discourse: They become opinion leaders, as well as having an agenda-setting effect, thus creating an alternate picture of public opinion. We also show that hyperactive users strongly influence specific types of recommender systems. By training collaborative filtering and deep learning recommendation algorithms on simulated political networks, we illustrate that models provide different suggestions to users, when accounting for or ignoring hyperactive behavior both in the input dataset and in the methodology applied. We attack the trained models with adversarial examples by strategically placing hyperactive users in the network and manipulating the recommender systems’ results. Given that recommender systems are used by all major social networks, that they come with a social influence bias, and given that OSNs are not per se designed to foster political discussions, we discuss the implications for the political discourse and the danger of algorithmic manipulation of political communication.

La madera madura de Eucalyptus camaldulensis presenta buenas propiedades tecnológicas y aptitud para la obtención de productos sólidos. La madera joven proveniente de orígenes de Eucalyptus camaldulensis posee características físicas y mecánicas diferentes a la madera adulta, pues presenta comportamientos no apropiados durante su transformación mecánica. El objetivo del trabajo fue determinar cuáles orígenes exhiben mejor comportamiento en el secado artificial, lo que indicaría la calidad de estas maderas. La madera para los ensayos de secado consistió en individuos pertenecientes a siete orígenes de Eucalyptus camaldulensis (a, b, c, d, e, k, ll). El material fue seleccionado con base en la altura, porte, diámetro altura de pecho (dap), densidad y estado sanitario. Las trozas fueron aserradas obteniéndose tablas de 100 mm de ancho x 25 mm de espesor x 1000 mm de largo, estando cada carga de secado compuesta por madera proveniente de los 7 orígenes. Los orígenes de los Eucalyptus camaldulensis jóvenes no presentaron una tendencia marcada al colapso en ningún programa de secado. En relación con los alabeos, los orígenes b, a, c y ll fueron superiores a los orígenes e y k; mientras que, en el caso de las rajaduras los orígenes d y ll fueron superiores.

New materials are being developed for architectural and design purposes. The recycling of waste is presented as an opportunity for new applications based on increased industrial waste and raw material shortages. Seeking an alternative to wooden panels, regional waste without sustainable disposal is being used as inputs in the production of lignocellulosic panels. We present the results of two experiments. The first one consists in the development of peanut husks ground-treated and untreated panels made in order to determine the influence of different particle sizes, shapes and their combinations, aiming to the physical and mechanical characterization of compact panels properties. In the second experiment, compact panels with whole peanut husks were made with polyurethane resin using castor oil painting. The object of this study was to analyze the influence of this new resin, without formaldehyde emissions, in the resulting panels physical and mechanical properties. It was concluded that the smaller particles had a positive influence in the panels physical-mechanical properties, and that the property characterization of panels made with castor oil resin was satisfactory for use in interior furniture. Peanut husks panels show good prospects for their integration in the field of design and architecture. Fil: Gatani, Mariana Pilar. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Cordoba. Centro Experimental de la Vivienda Economica(i); Argentina Fil: Granero, Victoria. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Cordoba. Centro Experimental de la Vivienda Economica(i); Argentina Fil: Medina, Juan Carlos. Universidad Nacional de Santiago del Estero. Facultad de Cs.forestales. Instituto de Tecnologia de la Madera; Argentina Fil: Fiorelli, Juliano. Universidade de Sao Paulo; Brasil Fil: Lerda, Maria Josefina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Cordoba. Centro Experimental de la Vivienda Economica(i); Argentina Fil: Sipowicz, Eugenia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Cordoba. Centro Experimental de la Vivienda Economica(i); Argentina Fil: Kreiker, Jeronimo Rafael. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Cordoba. Centro Experimental de la Vivienda Economica(i); Argentina

Objective/scope Breakthrough technologies for down-hole capture of radium-226 or hydrogen sulfide contaminants in fracking operations have been developed, and are presented here. These technologies could enable significant reduction in topside waste concentrations, and therefore simplify waste management operations and reduce expenses in fracking operations. These novel technologies still possess desirable primary functions of proppants such as flow back control and conductivity. Methods, procedures, process Multifunctional coatings supported by a variety of urethane chemistries were designed for down-hole capture of Ra-226 or H2S while preserving primary proppant functionality. Polymer coatings were applied to 20/40 or 20/30-mesh Northern White sand proppants. Coated proppants with Radium-capturing abilities were exposed to simulated brine spiked with Ra-226 in batch mode. Ra-226 was analyzed in the brine before and after treatment using liquid scintillation counting and in the solids using Gamma-ray spectrometry. The H2S-capturing proppants were exposed to water/tetradecane spiked with H2S, and H2S was analyzed in the headspace of the vessel containing proppant solution via gas chromatography. Results, observation, and conclusions In batch experiments, multifunctional resin coated proppant with Radium-capturing abilities (slurried at 20-33 wt% in brine) showed 2350-24000 pCi Ra-226 capture from synthetic brine /lb proppant used (water containing 5.0 wt% NaCl, 2.6 wt% CaCl2 and/or 0.07 wt% BaCl2·2H2O). The capture was dependent upon: concentration of salts in brine, initial concentration of Ra-226 (2500-35000 pCi/L), brine temperature (70-90 °C), and duration of exposure (1h - 1week). Radium capture was not affected by Na+ and Ca2+ concentration in the brine, but was significantly affected by Ba2+ concentration. Furthermore, other proppants were also designed to deliver only contaminant-capturing abilities. In this case, and under same experimental conditions, we observed up to 22000 pCi Radium capture/ lb proppant. This more economical approach can be used to impart only waste capturing functionality to proppants. Experiments in water at 70°C for 1 hour of exposure with multifunctional resin coated proppants for H2S capture showed 66-100% capture (initial [H2S] in liquid at equilibrium = 100 ppm, experimental capacity demonstrated ~1.1E-03 lb S removed/lb proppant used). Analogous H2S capture experiments in tetradecane solvent (simulated hydrocarbon) showed a slower rate of capture. Please explain how this paper will present novel (new) or additive information to the existing body of literatures that can be of benefit to a practicing engineer Presented multifunctional proppants can enable simplification of topside waste water treatment, enable waste water reusability, mitigate pipeline corrosion, and limit worker exposure by keeping key contaminants down-hole (Ra 226 or H2S) in the fractures. This is the first demonstration of truly multifunctional resin coated proppants that successfully capture waste from synthetic brine.

Objective: Among efforts to improve the well-being of healthcare professionals are initiatives based around mindfulness meditation. To understand the value of such initiatives, we conducted a systematic review of empirical studies pertaining to mindfulness in healthcare professionals. Method: Databases were reviewed from the start of records to January 2016. Eligibility criteria included empirical analyses of mindfulness and well-being outcomes acquired in relation to practice. 81 papers met the eligibility criteria, comprising a total of 3,805 participants. Studies were principally examined for outcomes such as burnout, distress, anxiety, depression, and stress. Results: Mindfulness was generally associated with positive outcomes in relation to most measures (although results were more equivocal with respect to some outcomes, most notably burnout). Conclusion: Overall, mindfulness does appear to improve the well-being of healthcare professionals. However, the quality of the studies was inconsistent, so further research is needed, particularly high-quality randomized controlled trials.

Resumen Introduccion Existe amplia evidencia de que tener una metodologia en la asistencia del politraumatizado es esencial, y es necesaria una correcta formacion del personal sanitario para poder llevarla a cabo. Material y metodo Describimos como hemos estructurado la atencion a estos pacientes en el Hospital de Torrevieja mediante la organizacion de una Unidad de Politraumatizados, un Comite de Politraumatizados y un Equipo de Trauma; como se realiza la formacion del personal (curso de politraumatizados) y describimos de manera prospectiva los resultados de los 2 anos de funcionamiento. Resultados Se atendieron 79 pacientes (3,4 al mes); de estos, el 38% tenia traumas combinados, el 35% tenia trauma toracico, el 15% tenia traumas en el torax y en el abdomen y el 12% tenia traumas en el abdomen. La causa mas frecuente de trauma fueron los accidentes de trafico y de arma blanca. Se activo el Equipo de Trauma en 27 ocasiones. La tasa de mortalidad fue del 8,8%. En este periodo se han realizado 5 cursos en los que han participado ya el 29,5% del personal al que va dirigido el curso. Conclusiones Es fundamental una adecuada protocolizacion en este tipo de pacientes y disponer de los medios para formar al personal.

Introduction Although there is ample evidence on the importance of having good protocols for Trauma patient care, a teaching system for the personnel involved in this care is needed. Methods The aim is to describe how we have organised the care for this type of patient in Hospital Torrevieja by creating a Trauma Surgery Unit, a Trauma Committee, and a Trauma Team. We also describe how we have developed training in order to ensure personnel get the knowledge and skills to care for these patients correctly (Trauma Surgery Course). Results We prospectively describe the results. Seventy-nine patients were attended to and 38% had sustained combined multiple injuries, 35% isolated thoracic trauma, 15% combined thorax and abdomen, and 12% abdomen. The most frequent cause of trauma was traffic accident, closely followed by stab wounds. Trauma team activation was made in 27 cases. Overall mortality rate was 8.8%. During this period of time, 5 editions of the course have been given and 29.5% of the target personnel have already participated in them. Conclusions We conclude by highlighting the importance of having adequate protocols for treating these patients and the correct means for teaching the personnel.

The aim of this study was to detect genotypic differences between three populations of healthy volunteers from Northern Spain (204 subjects), Nicaragua (120 subjects), and El Salvador (112 subjects) regarding CYP3A4*1B and CYP3A5*3 polymorphisms. No significant differences were found by comparing allelic frequencies between the two Central American populations. The CYP3A5*3 allele frequency was significantly different (P < 0.01) between Central Americans (76%) and Spaniards (91%). By contrast, CYP3A4*1B allele was more prevalent among Central Americans (12.5%) than among North Spaniards (4%) (P < 0.01). Analysis of CYP3A4-3A5 genotype combinations revealed that individuals carrying CYP3A4*1B/CYP3A5*1 were more represented in Central Americans (16.9%) than in Spaniards (5.4%), suggesting a marked linkage disequilibrium. These data are compatible with a higher CYP3A enzyme activity in Central Americans as opposed to Spaniards and other white groups, which could imply differences in dose requirements for drugs metabolized by CYP3A and should be considered in allele-disease association studies.

To describe and analyze the characteristics of prehospital medical assistance provided by the Madrid Municipal Emergency and Civil RescueProtection Service (SAMUR); and, based on the epidemiologic knowledge so gained, to prioritize public health intervention strategies.A retrospective cross-sectional analysis of all medical services performed by the SAMUR-Protección Civil in 2001 and 2002. Study variables included causes, response times, hour, day of the week, month, mobile resource, Municipal District, and pathology. For analysis purposes, the relevant data were linked to Access 97 via Open Database Connectivity. Statistical analysis was performed using the SPSS computer software package, with Spearman's correlation coefficient and analysis of variance. Values were deemed statistically significant at p0.05.The study population comprised the 97,937 and 101,438 interventions undertaken in 2001 and 2002, respectively. Mean daily activity in 2002 involved 278 alerts (standard deviation: 46), 95% confidence interval: 273-282. Distributions of the interventions were similar for 2001 and 2002, with peak activity from 1 to 2 pm and 8 to 9 pm, and minimum activity from 6 to 7 am. Activity was at its most intense on Saturdays. The magnitude of the association between the two years by day of the week was 96% (p0.001). The Central Municipal District (Centro) triggered 17,875 emergency actions. The prevalent pathology was traumatologic, followed by cardiovascular.Epidemiologic description enabled the characteristics of the prehospital assistance procedure to be comprehensively ascertained and quantified. False alarms assume special relevance due to their implications. Emergency medical alerts with a psychosocial component are on the increase, something that must be controlled.

Multidimensional gas chromatography (2D GC) is demonstrated as a way to improve limits of detectability of spectrophotometric detectors. UV and IR detectors are generally less sensitive than mass spectrometers or other GC detectors. This has placed some limitations on the useful capabilities provided by spectrophotometric detectors, such as the ability to provide structure-related information for a particular analyte. In this paper, we report results from interfacing a 2D GC instrument to a UV detector. Symmetry factor and the ratio of retention time divided by peak width did not show deterioration of the quality of chromatography when a megabore column was used with this detector. Furthermore, an increase in the limits of detectability over that attainable in a single-column system was realized by using the 2D GC system. However, the low flow (1 mL/min) imposed by the use of a microbore column (250 μm ID) caused significant tailing when the UV detector was used.

A previous investigation from our laboratory showed that the odor of live green peach aphids, Myzus persicae (Sulzer), highly attracts the convergent lady beetle, Hippodamia convergens Guérin-Méneville. In this study, we isolated the odor and identified it as (E)-β-farnesene (an aphid alarm pheromone) using gas chromatography – mass spectrometry. The olfactory response of the convergent lady beetle to (E)-β-farnesene was investigated using an eight-arm air-flow olfactometer and tracing the pathways of the lady beetles. The results clearly indicate that H. convergens can perceive and orient to (E)-β-farnesene released by green peach aphids. These findings suggest that this species of lady beetle has evolved a sensory system for detecting the green peach aphid alarm pheromone as a means of finding its prey.

Experimental peak capacities for capillary gas chromatography (GC), capillary liquid chromatography (CLC), and capillary electrochromatography (CEC) were compared. To obtain a meaningful comparison, the following constraints were applied. First, the same sample (mixture of alkylbenzenes) was used as a test mixture for all three techniques; second, the same packing material and column diameter were used in CLC and CEC; and third, isothermal conditions were used in GC, while isocratic conditions were used both in CLC and in CEC. Comparison of peak capacities for the same total column efficiency (approximately 36000 plates) showed that the peak capacity of GC is greater than those of the liquid-phase separation techniques. Comparison of CEC and CLC for constant retention factor was also carried out. For this condition, the results depend on the particle size used; for 3-microm porous particles, CEC had a peak capacity larger than CLC due to higher efficiency from the flow profile generated by electroosmotic flow. However, when 1.5-microm nonporous particles were used, the peak capacities were approximately the same for both techniques. The effect of linear velocity on peak capacity was also studied for all three techniques. Practical conditions aimed at increasing peak capacities of liquid-phase separation techniques are discussed.

A new gradient system for CEC was designed and adapted to a home-built CEC system. Chromatographic separations are initiated with a predetermined mobile phase composition and, after a desired time period, a syringe pump delivers pure organic solvent at a preset flow rate into a 2 mL vial used as the inlet buffer reservoir. Mixing is achieved by the use of a microstir bar in the buffer reservoir, which in turn is driven by an air-actuated stir plate. In this way, a convex-shaped gradient is generated, and the mobile phase is introduced into the separation column by electro-osmotic flow. Use of this system significantly reduced analysis time while still retaining acceptable reproducibility. Nonaqueous CEC was used for isocratic and gradient separation (

Three Argonne Premium Coals (Upper-Freeport, Pittsburgh #8, and Lewiston-Stockton) were extracted with benzene in both Soxhlet and pressurized fluid extraction (PFE) systems. The extracts were compared on the basis of dry mass yield and hydrocarbon profiles as obtained by gas chromatography/mass spectrometry. The dry mass yields (wt%, daf) indicated no difference by either method for the Upper-Freeport coal, but statistically different yields were obtained for the Pittsburgh #8 and Lewiston-Stockton coals. In this study, PFE required ∼90 vol.% less solvent compared to Soxhlet extraction. The gas chromatograms obtained from the Soxhlet extracts contained solvent contaminant peaks as dominant peaks, which were not observed in chromatograms of the PFE extracts. No thermal degradation, as indicated by excess phenolic compound concentrations, was noted in any of the PFE extracts.

Kinetic data from the literature were used to predict formation rates and product yields of oil and gas at typical low-temperature conditions of coal maturation. These data indicate that gas formation rates from hydrocarbon thermolysis are several orders of magnitude too low to have generated known coal-seam natural gas reserves, assuming bulk first-order kinetics defined by a single activation energy and preexponential factor. By assuming distributed activation energies, thermal cracking of liquid hydrocarbons and coal kerogen to methane can occur at sufficiently high rates to produce commercial quantities over long periods of geologic time. Acid-mineral-catalyzed cracking, transition-metal-catalyzed hydrogenolysis of liquid hydrocarbons, and transition-metal-catalyzed CO2 hydrogenation form gas at very high rates at geologic temperatures. Rates of gas production in these reactions are orders of magnitude higher than those predicted from thermolysis; moreover, the gaseous products for metal-catalyzed hyd...

Hydrocarbon hydrogenolysis and CO2 hydrogenation in the presence of Fe/SiO2 and Ni/SiO2 catalysts were evaluated as potential mechanisms contributing to natural gas formation in coalbeds. The hydrocarbons used as reactants in hydrogenolysis included butane, octane, 1-octene, and 1-dodecene. The reactions carried out in a laboratory batch reactor produced gas that contained methane concentrations greater than 90%, which resembles the composition of natural gas. Reaction temperatures were selected to resemble natural coalbed conditions. Evidence is presented to show that iron and nickel minerals, which can be present in coals at levels of 2000 and 10 ppm, respectively, can become active under geologic conditions. The oxides (Fe2O3 and NiO) used as precursors of the active catalysts (Fe and Ni metals) were reduced at 200°C under a hydrogen atmosphere. Mossbauer spectroscopy showed that ca. 6% of the iron oxide was converted to the metal; in the case of nickel, oxygen titration showed that the extent of reduction to the metal was ca. 29%. The resultant fractions of the active metals in coals are adequate to catalyze generation of appreciable amounts of methane over geologic time.

Iron-catalyzed CO2 hydrogenation is proposed as a mechanism that occurs during natural gas formation in coalbeds. This reaction was studied in a laboratory batch reactor at temperatures simulating geologic conditions. The percentage of methane in the produced gas was typically greater than 90%, resembling natural gas composition. Fe2O3, the precursor to the active catalyst, was reduced at 200°C under a hydrogen atmosphere. Mossbauer spectroscopy shows that under those conditions ca. 6% of the iron oxide is reduced to the metal, which is believed to be the catalytically active species. Addition of water to the reactor increased the generation of methane. No signs of deactivation were found under either dry or wet conditions. Evidence supporting the possibility that this reaction produces natural gas during coal maturation is provided.

Despite the great interest in coalbed gas formation mechanisms, detailed descriptions of instrumentation used for experimentation in such studies, especially laboratory reactors for measuring reaction rates under well-defined conditions, are scarcely found in the scientific literature. This communication describes the design, construction, and demonstration of a state-of-the-art batch reactor system with on-line analysis and data processing for measurement of gas formation rates. This system features complete on-line GC analysis of the gaseous compounds produced in the reactor as a function of reaction time. It is computer controlled and automated using software written in Visual Basic 5.0. The use of this reaction system is reported here for (1) quantitative analysis of gas-phase products from catalytic hydrogenolysis of hydrocarbons as well as CO2 hydrogenation, (2) real-time measurement of reaction parameters, including temperature and pressure, and (3) qualitative and quantitative analysis of gases desorbed from coal samples.