Let\u27s Play!

A day in the life of Paul Freeman

Life with Phillip

A brother and a best friend

Hydrogen (H2) sensing and catalysis with organic-stabilized Pd and Pd alloy nanoparticles.

This dissertation shows the hydrogen reactivity and stability of solid-state films and solutions of nanoparticles (NPs) for potential applications in hydrogen sensing and homogeneous catalysis of organic reactions. Mainly, this dissertation describes 1) the chemical synthesis of Pd and PdAg nanoparticles coated with various organic ligands and with different metal compositions, 2) the stability of solutions containing Pd and PdAg NPs in the presence of hydrogen, 3) the hydrogen sensing properties of films of NPs deposited onto Au microelectrodes, and 4) the evaluation of the catalytic activity of Pd and PdAg NPs for hydrogenation/isomerization of allyl alcohol. We chemically synthesized Pd and Pd-containing alloy (PdAg) NPs stabilized with alkanethiolates (CnS, n = 4, 6, 8, 12, 16, and 18), alkylamines (CnNH2, n = 8, 12, and 16), and mixed C8NH2/C6S ligands. All of the NPs were easily prepared and fully characterized by various analytical techniques to get their composition. By varying the initial mole ratio of Pd/CnNH2 and the chain lengths of CnNH2 and CnS, we were able to control the size, distribution, and stability of the NPs. When these NPs were exposed to 100% hydrogen, different stability was observed depending on the functionality and composition of Pd and PdAg NPs. While CnS Pd NPs (n = 6) had high stability against H2-induced aggregation because of the strong Pd-S interaction and moderate-sized alkane chain, the 6x and 12x C16NH2 Pd and Pd91Ag9 NPs exhibited the highest stability likely due to the formation of a bilayer of ligands on the Pd core that prevents the NP aggregation. For mixed ligand C8NH2/C6S Pd NPs, the stability strongly depended on the C8NH2/C6S ratio on the Pd NPs. The Pd NPs coated with ~3:1 or less C8NH2/C6S ligands showed excellent stability against H2-induced aggregation in solution. In the area of hydrogen sensing, neither C6S Pd nor C8NH2 Pd NPs displayed desirable sensing attributes. By synthesizing C8NH2/C6S mixed Pd NPs with controlled ratios, we were able to prepare films of these NPs that displayed stable, reversible sensing behavior to H2 gas down to 0.3%. In the area of catalysis, we synthesized a wide range of NPs with different composition and functionality. We discovered that the functionality plays a large role in the stability, selectivity, and reactivity of the catalysts. First, the NPs that are not stable showed very low turnover frequency (TOF) values since they were behaving as heterogeneous catalysts with lower surface area. For those that are stable, the strong thiolate ligands hindered the reaction rate, but provided a very interesting selectivity to form the aldehyde from allyl alcohol. In contrast, the very stable, but weak binding C16NH2 ligands led to Pd NPs with high reactivity, but little selectivity, forming both products. We learned that the long alkyl chain does not hinder the reaction very much as long as the ligand binds weakly. We also evaluated the catalytic properties of C6S and C16NH2 Pd and PdAg NPs for the hydrogenation/isomerization of various allyl alcohols that differ only slightly in chemical structure. We observed that the more branched substrates have low TOF, likely due to the strong Pd-S interaction and to restricted diffusion and access to active sites through the packed multilayer of C16NH2 ligands surrounding the Pd core. Interestingly, the C6S Pd NPs led to hydrogenation reaction when isomer formation is not possible. Importantly, by varying the H2 flow rate, we could favor the isomerization or hydrogenation. In the case of Pd NPs coated with CnS ligands, we determined that these catalysts are highly selective for isomerization reactions and that the carbon chain length does not impede the reactivity of the NPs. C8S Pd NPs may be the optimal catalysts in terms of reactivity and stability. Our research has led to new fundamental insights about the reactivity between hydrogen and various Pd-containing NPs that may allow for rational design of metal NPs for specific sensing and catalysis applications

Bridging the Gap Between the Least and the Most Influential Twitter Users

Social networks play an increasingly important role in shaping the behaviour of users of the Web. Conceivably Twitter stands out from the others, not only for the platform's simplicity but also for the great influence that the messages sent over the network can have. The impact of such messages determines the influence of a Twitter user and is what tools such as Klout, PeerIndex or TwitterGrader aim to calculate. Reducing all the factors that make a person influential into a single number is not an easy task, and the effort involved could become useless if the Twitter users do not know how to improve it. In this paper we identify what specific actions should be carried out for a Twitterer to increase their influence in each of above-mentioned tools applying, for this purpose, data mining techniques based on classification and regression algorithms to the information collected from a set of Twitter users.This work has been partially founded by the European Commission Project ”SiSOB: An Observatorium for Science in Society based in Social Models” (http://sisob.lcc.uma.es) (Contract no.: FP7 266588), ”Sistemas Inalámbricos de Gestión de Información Crítica” (with code number TIN2011-23795 and granted by the MEC, Spain) and ”3DTUTOR: Sistema Interoperable de Asistencia y Tutoría Virtual e Inteligente 3D” (with code number IPT-2011-0889- 900000 and granted by the MINECO, Spain

El estudio de la justicia social en la perspectiva de los partidos políticos en México.

En el anexo se muestra un cuadro comparativo de las plataformas electorales de los partidos políticos y el formato de un cuestionario de opinión.El propósito de esta investigación es ahondar en los documentos doctrinarios y las plataformas políticas de tres partidos de estudio: Partido de Acción Nacional, PAN; Partido Revolucionario Institucional, PRI; y Partido de la Revolución Democrática, PRD; a fin de identificar sus tendencias ideológicas. Con base en los documentos se sustraen rubros que encaminan el estudio de la justicia social, se conceptualizan a la luz de tres ideologías que representan cada partido político y se someten a la percepción ciudadana mediante encuestas a fin de identificar la ubicación ideológica con respecto a la identificación partidista de los ciudadanos encuestados, los resultados arrojaron que existe una congruencia entre ambas ideas y mediante este conducto se podrán definir las posturas de cada individuo que encaminen la toma de sus decisiones políticas y posturas frente a temas de agenda nacional como educación, salud, empleo, vivienda, recaudación fiscal, así como reformas sociales, reforma hacendaria, etc. La pregunta de investigación se centra en ¿Cómo perciben los individuos algunos temas relacionados con la calidad y pertinencia de servicios públicos, infiriendo que la apuesta por su calidad y cobertura hacen posible la construcción de la justicia social, a la luz de su identificación partidista? ¿Cómo se da la relación entre la identificación partidista y la auto ubicación ideológica de los encuestados?, ¿Dicha relación influye en la percepción de los individuos sobre los servicios que ofrece el Estado? La importancia de la investigación radica en profundizar algunos elementos con respecto al comportamiento de los individuos identificados ideológicamente con algún partido político y su percepción con respecto a algunos servicios públicos, para acrecentar la brecha de justicia social. El creciente aumento de la pobreza, la disputa permanente por proteger los derechos sociales, económicos, políticos, el aumento de la desigualdad entre países y al interior de estos, es parte del paisaje que viven millones de personas. Bajo esta lógica, parece imprescindible conocer, analizar y construir a la luz de esos fenómenos una de las teorías contemporáneas de la justicia de Rawls, porque ha instalado el concepto de justicia social e influenciado nuevas y viejas reflexiones al respecto, especialmente dentro del marco del Estado Liberal

Optimizing Sepsis Management Through Enhanced Protocol Compliance in the Emergency Department

Problem: This quality improvement project aims to enhance early sepsis management and sepsis bundle compliance among Emergency Department nurses to reduce the risk of sepsis-related deaths as well as hospital length of stays. Context: A microsystem assessment, in the emergency department (ED) unit, was performed in Hospital A located in the Greater San Francisco Bay area by Clinical Nurse Leader (CNL) students. This ED unit cares for a variety of critical care patients ranging from urgent to life-threatening conditions. Intervention: An intervention was not implemented in the ED unit due to time constraints and limitations; however, CNL students provided recommendations so stakeholders could further investigate and implement them. The recommended interventions include increasing sepsis bundle training frequency, refining intravenous placement skills through training and readily available resources, establishing a standardized sepsis protocol, providing nurses badge buddies, and revising the current charting system. Measures: CNL students collected data to evaluate current sepsis care management and the rates of sepsis-related complications at the ED. The pre-intervention survey highlighted areas of improvement where proposed recommendations could help nurses utilize and adhere to sepsis bundle care more effectively. Results: The most relevant pre-intervention questionnaire results revealed that 42% of ED nursing staff recommend protocol revision, 24.4% claim to not have attended any sepsis training with another 4.9% reporting rarely attending, and 46.3% reported there is no debriefing, or follow-up training, when sepsis bundle compliance is failed to be met. In addition, nurses identified barriers to meeting compliance such as difficult IV access or “hard sticks”, standing orders, and knowledge gaps. Conclusions: A pre-intervention questionnaire given to ED nurses at Hospital A reveals gaps in knowledge and barriers to current sepsis management. Implementing a standardized sepsis protocol and offering nurses’ frequent sepsis bundles and intravenous training is recommended. The implementation of these recommended resources will hopefully improve nurses’ sepsis care management, improving patient outcomes and care quality. Keywords: Sepsis, Emergency Department, Sepsis Bundle Compliance, Sepsis Management, Quality Improvement Project, Microsystem, Sepsis Trainin

On the decorrelation of filter-bank energies in speech recognition

Cepstral coefficients are widely used in speech recognition. In this paper, we claim that they are not the best way of representing the spectral envelope, at least for some usual speech recognition systems. In fact, cepstrum has several disadvantages: poor physical meaning, need of transformation, and low capacity of adaptation to some recognition systems. In this paper, we propose a new representation that significantly outperforms both mel-cepstrum and LPC-cepstrum techniques in both recognition rate and computational cost. It consists of filtering the frequency sequence of filter-bank energies with an extremely simple filter that equalizes the variance of the cepstral coefficients. Excellent results of the new technique using a continuous observation density HMM recognition system and two very different recognition tasks, connected digits and phone recognition, are presented.Peer ReviewedPostprint (published version