Películas delgadas de V2O5 modificado con Ag depositadas utilizando configuraciones alternativas basadas en plasmas de ablación láser para su aplicación en sistemas fotocatalíticos

En este trabajo de investigación doctoral, se proponen tres configuraciones no convencionales de la técnica de ablación láser para preparar películas delgadas basadas en oxido de vanadio modificadas con diferentes cantidades de plata de manera controlada. A pesar de que la técnica de ablación láser ha sido ampliamente utilizada para preparar películas delgadas de una amplia gama de materiales, es una técnica poco adecuada para preparar películas delgadas formadas por materiales de diferente naturaleza, como es el caso de los denominados compositos. Con el propósito de contribuir a resolver este problema, se ha propuesto utilizar tres configuraciones alternativas basadas en ablación láser; en dos de las configuraciones propuestas se hacen interaccionar dos plasmas producidos simultáneamente a partir de materiales diferentes, en un caso, los plasmas se propagan en direcciones paralelas, en el otro, se utiliza una configuración de blancos múltiples, mientras que en el tercero se combina el plasma de ablación con un vapor producido por evaporación térmica. Con estas configuraciones se han preparado películas delgadas de óxido de vanadio con diferentes contenidos de plata que dan lugar a oxido de vanadio, así como diferentes vanadatos de plata en algunos casos decorados con nanopartículas de plata. Se evaluó la actividad fotocatalítica de las películas delgadas obtenidas con las diferentes configuraciones en la degradación de una solución de verde de malaquita empleando luz solar simulada con buenos resultados. Es importante mencionar que, hasta donde sabemos, los materiales obtenidos no han sido preparados utilizando estas configuraciones experimentales, lo que le confiere a este trabajo de tesis originalidad.A la Universidad Autónoma del Estado de México (UAEM), al Instituto Nacional de Investigaciones Nucleares (ININ) y a la Universidad Autónoma Metropolitana campus Iztapalapa (UAM-I) por las facilidades otorgadas para los estudios de doctorado. Al Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM (CCIQS). Al Consejo Nacional de Ciencia y Tecnología (CONACyT) por la beca otorgada para los estudios de Doctorado y Beca Mixta con numero de becario CVU 325795 y al financiamiento a través de los proyectos CB-168827 y CB-240998 A la SIEA por la beca otorgada Movilidad Estudiantil de Estudios Avanzados 201

The Flow Fingerprinting Game

Linking two network flows that have the same source is essential in intrusion detection or in tracing anonymous connections. To improve the performance of this process, the flow can be modified (fingerprinted) to make it more distinguishable. However, an adversary located in the middle can modify the flow to impair the correlation by delaying the packets or introducing dummy traffic. We introduce a game-theoretic framework for this problem, that is used to derive the Nash Equilibrium. As obtaining the optimal adversary delays distribution is intractable, some approximations are done. We study the concrete example where these delays follow a truncated Gaussian distribution. We also compare the optimal strategies with other fingerprinting schemes. The results are useful for understanding the limits of flow correlation based on packet timings under an active attacker.Comment: Workshop on Information Forensics and Securit

Spatial distribution patterns and movements of Holothuria arguinensis in the Ria Formosa (Portugal)

Holothurian populations are under pressure worldwide because of increasing demand for beche-de-mer, mainly for Asian consumption. Importations to this area from new temperate fishing grounds provide economic opportunities but also raise concerns regarding future over-exploitation. Studies on the habitat preferences and movements of sea cucumbers are important for the management of sea cucumber stocks and sizing of no-take zones, but information on the ecology and behavior of temperate sea cucumbers is scarce. This study describes the small-scale distribution and movement patterns of Holothuria arguinensis in the intertidal zone of the Ria Formosa national park (Portugal).Mark/recapture studieswere performed to record theirmovements over time on different habitats (sand and seagrass). H. arguinensis preferred seagrass habitats and did not show a size or life stage-related spatial segregation. Its density was 563 ind. ha−1 and mean movement speed was 10 m per day. Movement speed did not differ between habitats and the direction of movement was offshore during the day and shoreward during the night. Median home range size was 35 m2 and overlap among home ranges was 84%. H. arguinensis' high abundance, close association with seagrass and easy catchability in the intertidal zone, indicate the importance of including intertidal lagoons in future studies on temperate sea cucumber ecology since those systems might require different management strategies than fully submerged habitats

Assessing the Distributive Impact of More than Doubling the Minimum Wage: The Case of Uruguay

This paper analyzes the role of the sharply increases in the minimum wage after 2004 in Uruguay in the slight decrease on wage inequality. We Önd no impact of the miminum wage increases on wage inequality. This results can be explained by the low starting level of the minimum wage or lack of compliance with it. The Uruguayan experience shows that the minimum wage is not always e§ective as a redistribution instrument.minimum wage, wage inequality, IV, semiparametric estimation

Preparation and characterization of α-Fe nanowires located inside double wall carbon nanotubes

Capillary effect was used to fill double wall carbon nanotubes (DWCNT) with iron. The samples are characterized by Mössbauer and Raman spectroscopies, TEM, SAED, and magnetization. The experimental results indicate the presence of a-Fe nanowires inside the DWCNTs. The samples are ferromagnetic at room temperature. There are three striking results due to the confinement effects on the physical behavior of a-Fe: the hyperfine fields increase, the Debye temperature decreases and Raman modes are observed

Water nationalization: network access, quality, and health outcomes

In the case of natural monopolies there tends to be a trade-off between a higher quality of output provided by private firms, and a better access for poor consumers provided by public firms. This is partly the reflection of differences in objectives by private and public firms. The former tend to be product-driven, whereas the latter tend to base decisions on political agendas (Chong and Lopez de Silanes, 2005). The objective of this paper is to explore the impact on network access, water quality, and health outcomes of Uruguay's nationalization of water services. An important advantage of focusing on nationalization rather than privatization is that it avoids selection bias due to cherry-picking by firms or governments at the time of privatization. Indeed, nationalization in Uruguay affected all previously privatized firms, as water was declared "part of the public domain". Results suggest that the change in ownership led to an increase in the sanitation rate, as well as improvements in water quality. It was also accompanied by a decline in water-related child mortality, although this latter effect tends not to be statistically significant across specifications.minimum wage, wage inequality, IV, semiparametric estimation

Effect of cytostatic drugs on microbial behaviour in membrane bioreactor system

The aim of this work is to evaluate the influence of cyclophosphamide and its principal metabolites (CPs) on microbial behaviour in a membrane bioreactor system. Two laboratory-scale membrane bioreactors (MBR) were run in parallel with a sludge retention time of 70 days (one with the cytostatic drugs, MBR-CPs, the second without, MBR-control). The microbial activity was measured by respirometric analysis. The endogenous and exogenous respirations of heterotrophic micro-organisms were evaluated. Micro-organisms exposed to CPs showed higher endogenous respiration rates and lower exogenous respiration rates than micro-organisms present in MBR-control. The effects were observed several days after adding the cocktail. Reduced sludge production was observed in MBR-CPs compared to MBR-control. This reduction of sludge production and the increase in the endogenous respiration rate in relation to MBR-control suggest that the chemical stress caused by CPs led to a diversion of carbon and/or energy from growth to adaptive responses and protection. In addition, the inhibitory effect on the assimilation of exogenous substrate (reduced exogenous respiration rate) suggests an inhibition of catabolism and anabolism despite the low CPs concentration studied (μg/L). However, this inhibitory effect can be offset by the biomass still active under low ratio (substrate/biomass) conditions in the bioreactor (due to complete retention of biomass and high sludge age), which helped to maintain high overall performance in the removal of conventional pollution