Synthesis and Characterization of Fe8-based Materials as Electron Acceptors for Solar Energy Applications

The urgent need to find alternative sources of energy has been recognized as a major challenge of the 21st century. Many ideas have been proposed, but harvesting the energy of the Sun has been identified by many as the most promising alternative to satisfy the world’s increasing energy demand. Among the current technologies to harness solar energy, photovoltaics and artificial photosynthesis (photocatalysis) stand out. Although very different in their strategies, both technologies entail a core principle, the generation of a charge-separated state. To this end, both methods employ electron acceptors that will receive the photo-electron; in most cases this role is played by C60 or its derivatives. Our research group has synthesized and characterized an octanuclear iron-oxo cluster with remarkable electrochemical properties which compares favorably with the reduction potentials of C60 and derivatives. This dissertation explores the use of this octanuclear cluster as electron acceptor for solar energy applications. To assess the viability of Fe8 as an electron acceptor in photocatalysis, electron donors that could coordinate to its iron atoms via phenol groups were synthesized and characterized. These electron donors were used in efforts to make molecular dyads, but coordination was not achieved. The altenative strategy studied was the preparation of Fe8-based hybrid materials that can be casted with known polymer electron donors. Several hybrid materials were prepared and their general properties investigated. These materials exhibited the desired electrochemical traits as well as the general castable behavior of the polymer host. These hybrids are now ready to be tested in polymer solar cells

An Analysis of Optimal Tax Revenue Sharing for Mexico

We develop an analysis that identifies the characteristics of an optimal system of shared tax collection and intergovernmental transfers. Mathematical optimization is used to find the level of taxes and intergovernmental transfers. Formulas for the optimal level of taxes and transfers to subnational governments are characterized. We suggest reforms to intergovernmental transfers to include the costs of tax inefficiency, some tax equalization transfer rules, and the marginal social benefits of local public spending. Future research could include local public spending with regional externalities, migration, and consider a dynamic model. This article proposes an original theoretical model of optimal tax coordination and transfers. The optimal level of taxes and transfers are identified. This paper proposes reforms to the participation formula for subnational governments.Un análisis de la participación óptima en los ingresos fiscales de MéxicoSe desarrolla un análisis que identifica las características de un sistema óptimo de recaudación tributaria compartida y transferencias intergubernamentales. Se utiliza la técnica de optimización para encontrar el nivel de impuestos y transferencias intergubernamentales. Se caracterizan fórmulas para el nivel óptimo de impuestos y transferencias a gobiernos subnacionales. Reformar las participaciones al incluir los costos de ineficiencia de los impuestos, algunas normas de transferencias de ecualización fiscal, y los beneficios sociales marginales del gasto público local. Para futuras investigaciones se podrían incluir el gasto público local con externalidades regionales, la migración, y considerar un modelo dinámico. Este artículo propone un modelo teórico original de coordinación de impuestos y transferencias óptimas. Se identifican el nivel óptimo de impuestos y transferencias. Este trabajo propone reformas a la fórmula de participaciones a gobiernos subnacionales

Remittances and the Size and Composition of Government Spending

Objective. We study the effect of remittances on the size and composition of public spending. Methodology. An optimization technique is used to develop a dynamic theoretical model and a simulation analysis. Results. It is demonstrated that remittances have a positive income effect on public goods, but a negative income effect and a price effect on social transfers, which explains why public goods increase, but social transfers can increase or fall due to changes in the remittances. Recommendations. The model makes recommendations for public policy design by characterizing the optimal level of public spending. Limitations. It is desirable to extend our analysis to consider electoral incentives and thus provide different explanations of how remittances might affect public spending. Originality. To the best of our knowledge, this is the first document that develops a theory to explain the effect of remittances on the size and composition of public spending. Conclusions. Remittances have a differentiated effect on public goods and social transfers depending on the income and price effects that affect the composition of public spending. Remesas y el Tamaño y Composición del Gasto del Gobierno Objetivo. Estudiar el efecto de las remesas en el tamaño y composición del gasto público. Metodología. Se utiliza la técnica de optimización para desarrollar un modelo teórico-dinámico y un análisis de simulación. Resultados. Se muestra que las remesas tienen un efecto ingreso positivo en los bienes públicos, pero en un efecto ingreso negativo y un efecto precio en las transferencias sociales lo que explica por qué los bienes públicos aumentan, pero las transferencias sociales pueden aumentar o caer por cambios en las remesas. Recomendaciones. El modelo hace recomendaciones de diseño de política pública al caracterizar el nivel de gasto público óptimo. Limitaciones. Es deseable extender nuestro análisis para considerar los incentivos electorales y así proporcionar diferentes explicaciones de cómo las remesas afectan el gasto público. Originalidad. Hasta donde sabemos, este es el primer documento que busca explicar el efecto de las remesas en el tamaño y composición del gasto público. Conclusiones. Las remesas tienen un efecto diferenciado en bienes públicos y transferencias sociales dependiendo de los efectos ingreso y precios que afectan la composición del gasto público.

Social networks in the single cell

Plant mitochondrial DNA (mtDNA) can become damaged in many ways. A major repair mechanism is homologous recombination, which requires an undamaged DNA template. Presumably, this template comes from a different mitochondrion in the same cell. Plant mitochondria undergo fission and fusion to form transient networks which could allow the exchange of genetic information. To test this hypothesis, Chustecki et al. (2022) used msh1 mutants with defective DNA repair, and showed that mitochondrial interactions increased, revealing a link between the physical and genetic behavior of mitochondria

Multiplicity in Early Stellar Evolution

Observations from optical to centimeter wavelengths have demonstrated that multiple systems of two or more bodies is the norm at all stellar evolutionary stages. Multiple systems are widely agreed to result from the collapse and fragmentation of cloud cores, despite the inhibiting influence of magnetic fields. Surveys of Class 0 protostars with mm interferometers have revealed a very high multiplicity frequency of about 2/3, even though there are observational difficulties in resolving close protobinaries, thus supporting the possibility that all stars could be born in multiple systems. Near-infrared adaptive optics observations of Class I protostars show a lower binary frequency relative to the Class 0 phase, a declining trend that continues through the Class II/III stages to the field population. This loss of companions is a natural consequence of dynamical interplay in small multiple systems, leading to ejection of members. We discuss observational consequences of this dynamical evolution, and its influence on circumstellar disks, and we review the evolution of circumbinary disks and their role in defining binary mass ratios. Special attention is paid to eclipsing PMS binaries, which allow for observational tests of evolutionary models of early stellar evolution. Many stars are born in clusters and small groups, and we discuss how interactions in dense stellar environments can significantly alter the distribution of binary separations through dissolution of wider binaries. The binaries and multiples we find in the field are the survivors of these internal and external destructive processes, and we provide a detailed overview of the multiplicity statistics of the field, which form a boundary condition for all models of binary evolution. Finally we discuss various formation mechanisms for massive binaries, and the properties of massive trapezia.Comment: Accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Hennin

Crystal structure of methyl N-ferrocenylcarbamate

The asymmetric unit of the title compound, [Fe(C5H5)(C7H8NO2)], contains two independent molecules consisting of a ferrocenyl moiety and a nitrogen-bound methyl carbamate. These units are almost perpendicular to each other, making dihedral angles of 87.74 (9) and 87.32 (8)°. In each independent molecule, the cyclopentadienyl rings deviate slightly from an eclipsed conformation and lie virtually parallel [dihedral angles = 1.42 (15) and 0.49 (13)°]. In the crystal, molecules are linked by N—H...O hydrogen bonds into chains along the a-axis direction

Small power load disaggregation in office buildings based on electrical signature classification

This paper assesses the application of Non-Intrusive Appliance Load Monitoring (NIALM) methods for disaggregating electricity consumption in office buildings. The focus of the research is on small power equipment, which can represent up to 50% of the electricity use in buildings fitted with high efficiency building services. Research in this field has led to numerous algorithms being developed for use with NIALM systems, however, due to the highly variable nature of electrical appliances no suitable common characteristic has been identified for disaggregation. This paper presents an analysis of a set of electrical signatures based on transient and current-voltage phase shift during steady-state conditions for which subsets of the signatures are considered for identifying different small power loads. The ability of this approach to disaggregate appliance loads is demonstrated with the idea of applying disaggregation techniques during energy audits of office buildings

General Bound on the Rate of Decoherence

We establish the necessary and sufficient conditions for a quantum system to be stable under any general system-environment interaction. Quantum systems are stable when the time-derivative of their purity is zero. This stability provides a dynamical explanation of the classicality of measurement apparatus. We also propose a protocol to detect global quantum correlations using only local dynamical information. We show how quantum correlations to the environment provide bounds to the purity rate, which in turn can be used to estimate dissipation rates for general non-Markovian open quantum systems.Chemistry and Chemical Biolog

Propuesta de diseño de pavimento con geometría Optimizada para evitar agrietamiento en la Calle Zarumilla Cuadra 17, Jaén, Cajamarca

El objetivo fue proponer el diseño de pavimento con Geometría Optimizada para evitar agrietamiento en la calle Zarumilla Cuadra 17, Jaén, Cajamarca. La metodología fue: Investigación de tipo aplicada. Según su enfoque es cuantitativo por el uso del software OptiPave 2 y según su alcance es de tipo descriptivo al especificarse los parámetros y características del proceso de diseño estructural del pavimento. El diseño es no experimental transversal descriptivo correlacional causal. La muestra es la calle Zarumilla Cuadra 17 del distrito de Jaén, Provincia de Jaén de la Región Cajamarca. La población es la infraestructura vial del distrito de Jaén; siendo una muestra no probabilística. Tenemos como resultados propuestos: En el diseño del pavimento largo de losa 1.75 m, espesor 130 mm, porcentaje de losa agrietada 4.16% al finalizar la vida útil del pavimento, escalonamiento 0.07 mm e IRI 2.44 m/km. Conclusión: Se acepta la hipótesis general “el pavimento con Geometría Optimizada evitará el agrietamiento en la calle Zarumilla Cuadra 17, Jaén, Cajamarca