Lead accumulation by hammerhead shark, Sphyrna couardi (C.) off Lagos coast, Nigeria

Levels of concentration of lead in the hammerhead shark, Sphyrna couardi, off the Lagos Coast of Nigeria were investigated. The standard length of the specimens examined ranged from 31.4cm to 47.2cm while the weights ranged from 451.5 to 1,667g. The lead concentration ranged from 0.11 degree kg/G to 0.38 degree kg/G. The mean lead concentration was 0.56 degree kg/G (dry weight). The gill has the highest lead concentration. There was no linear correlation between the length and weight and the amount of lead concentrated

Desarrollo de una aplicación para una red de sensores inalámbricos (WSN) mediante Contiki

Durante los últimos años hemos venido observando la tendencia a incorporar capacidad de proce- samiento y comunicación a dispositivos que hasta entonces se utilizaban de modo independiente. La evolución de los móviles a smartphones es un claro ejemplo de dicha tendencia, aunque también cabe mencionar otros ejemplos, como es el caso de los denominados hogares inteligentes, en los que elementos del hogar se encuentran interconectados y pueden actuar de modo conjunto. Esta ten- dencia no se limita a sistemas independientes, sino que propone interconectar todos los elementos disponibles para conformar la denominada Internet de los Objetos/Cosas o Internet of Things, IoT. Una de las mayores dificultades que se presenta en estos sistemas es que las características de es- tos nuevos dispositivos inteligentes, en general limitados en términos de cómputo, almacenamiento, autonomía o comunicación, queda a menudo lejos de los equipos informáticos tradicionales. Esta cuestión, junto con la ausencia de estándares para gestionar estos dispositivos, constituye un impor- tante problema a abordar. Considerando este marco, en este proyecto se ha desarrollado una aplicación orientada a este tipo de dispositivos. Más concretamente, la aplicación tiene como soporte una red de sensores inalámbricos, WSN, con el objetivo de realizar seguimiento de individuos. Cabe destacar que el desarrollo de la aplicación se ha realizado utilizando Contiki OS, sistema ope- rativo diseñado especialmente para dispositivos con características limitadas como los presentados anteriormente y firme candidato a convertirse en estándar.

Soporte a la explotación de datos y gestión de una red de sensores

El seguimiento de distintas especies de animales contribuye en gran medida a su estudio y, por tanto, a su conservación y control. Los avances tecnológicos de los últimos años han facilitado las posibilidades de seguimiento con la creación de distintos dispositivos que permiten conocer los movimientos de la especie que se desea estudiar. Uno de los sistemas más utilizados consiste en la utilización de dispositivos GPS incorporados al espécimen sobre el que se realiza el seguimiento y cuya señal es recogida por satélites que se encargan de almacenar y posteriormente reenviar la información para su almacenamiento y procesamiento en el laboratorio. El principal problema de este sistema es su elevado coste. Existen alternativas que no presentan un coste tal alto, tales como el uso de módulos basados en telefonía móvil. Sin embargo, tienen limitaciones de cobertura, por lo que no es aplicable en todos los ámbitos. Este proyecto forma parte de una propuesta que ofrece realizar seguimiento de ejemplares de una especie de ave, la gaviota Patiamarilla, en Gipuzkoa mediante la utilización de una red de sensores y que tiene varias ventajas frente a las opciones presentadas anteriormente. En este proyecto en concreto se ha diseñado e implementado el módulo que permite recoger la información obtenida por el conjunto de sensores (cada ejemplar lleva incorporado un sensor que permite registrar su posición) y enviarla a un servidor centralizado para su posterior consulta y análisis. Adicionalmente, también se permite consultar el último estado registrado de cada dispositivo de seguimiento, además de contemplar la posibilidad de actualizar su software.

Optimización del Lead Time de vehículos mediante la implementación de una solución RTLS (Real Time Location System)

A lo largo de este documento, se va a explicar la implantación del proyecto que he realizado basado en la localización de vehículos en la fábrica de Mercedes Benz España situada en Vitoria-Gasteiz. Durante la realización de este proyecto, se han llevado a cabo diversos estudios con el fin de conseguir la correcta implantación de las tecnologías empleadas. Se han realizado diferentes alternativas de posicionamiento de los componentes y diversas pruebas para comprobar el correcto funcionamiento de la solución. La solución del proyecto se realizará en distintas fases. La primera de ellas tratará sobre el estudio en una determinada zona de la fábrica, más concretamente la denominada “Área Técnica”, en esta zona se encuentran los vehículos que sufren algún retoque una vez están montados, esta zona se utilizará como piloto para una vez finalizado y comprobado su éxito ampliar la solución al resto de zonas. Previamente a mi incorporación se realizó un estudio para la colocación de los elementos necesarios en esta zona y se ha visto las posibilidades y beneficios que aportaría el control de los vehículos dentro de la fábrica. La siguiente fase será implantar la solución en el resto de las áreas que se encuentran dentro de la fábrica de Vitoria-Gasteiz así como la instalación de unos dispositivos que estarán ubicados en las puertas. Estos ayudarán a mejorar la ubicación de los vehículos ya que podremos conocer si los vehículos se encuentran dentro o fuera de la fábrica. Finalmente se ha realizado la integración de la solución en los sistemas actuales que utilizan en la fábrica para la gestión de los vehículos durante su ciclo de vida.

Noninterferometric measurement of lead zirconate titanate inverse piezoelectric extension

A noncontacting and noninterferometric depth discrimination technique, which is based on differential confocal microscopy, was used to measure the inverse piezoelectric extension of a piezoelectric ceramic lead zirconate titanate actuator. The response characteristics of the actuator with respect to the applied voltage, including displacement, linearity, and hysteresis, were obtained with nanometer measurement accuracy. Errors of the measurement have been analyzed. (C) 2001 Society of Photo-Optical Instrumentation Engineers.

Red-shift conical emission by femtosecond pulses at low input power

Red-shift conical emission (CE) is observed by femtosecond laser pulse propagating in BK7 at a low input power (compared to those input powers for generation of blue-shift CE). With the increasing input power the blue-shift CE begins to appear whereas the red-shift CE ring (902 nm in our experiment) disappears accompanied by the augment of the central white spot size synchronously. The disappearing of red-shift CE in our experiment is explained such that the increase of axial intensity is much higher than that of ring emission and the augment of the central white spot size with the increasing input laser power.

Red shift and broadening of backward harmonic radiation from electron oscillations driven by femtosecond laser pulse

The characteristics of backward harmonic radiation due to electron oscillations driven by a linearly polarized fs laser pulse are analysed considering a single electron model. The spectral distributions of the electron's backward harmonic radiation are investigated in detail for different parameters of the driver laser pulse. Higher order harmonic radiations are possible for a sufficiently intense driving laser pulse. We have shown that for a realistic pulsed photon beam, the spectrum of the radiation is red shifted as well as broadened because of changes in the longitudinal velocity of the electrons during the laser pulse. These effects are more pronounced at higher laser intensities giving rise to higher order harmonics that eventually leads to a continuous spectrum. Numerical simulations have further shown that by increasing the laser pulse width the broadening of the high harmonic radiations can be controlled.

High temperature transport properties of lead chalcogenides and their alloys

This thesis describes a series of experimental studies of lead chalcogenide thermoelectric semiconductors, mainly PbSe. Focusing on a well-studied semiconductor and reporting good but not extraordinary zT, this thesis distinguishes itself by answering the following questions that haven’t been answered: What represents the thermoelectric performance of PbSe? Where does the high zT come from? How (and how much) can we make it better? For the first question, samples were made with highest quality. Each transport property was carefully measured, cross-verified and compared with both historical and contemporary report to overturn commonly believed underestimation of zT. For n- and p-type PbSe zT at 850 K can be 1.1 and 1.0, respectively. For the second question, a systematic approach of quality factor B was used. In n-type PbSe zT is benefited from its high-quality conduction band that combines good degeneracy, low band mass and low deformation potential, whereas zT of p-type is boosted when two mediocre valence bands converge (in band edge energy). In both cases the thermal conductivity from PbSe lattice is inherently low. For the third question, the use of solid solution lead chalcogenide alloys was first evaluated. Simple criteria were proposed to help quickly evaluate the potential of improving zT by introducing atomic disorder. For both PbTe1-xSex and PbSe1-xSx, the impacts in electron and phonon transport compensate each other. Thus, zT in each case was roughly the average of two binary compounds. In p-type Pb1-xSrxSe alloys an improvement of zT from 1.1 to 1.5 at 900 K was achieved, due to the band engineering effect that moves the two valence bands closer in energy. To date, making n-type PbSe better hasn’t been accomplished, but possible strategy is discussed.

Pulse NMR in solids : chemical shift, lead fluoride and thorium hydride

Part one of this thesis consists of two sections. In the first section the fluorine chemical shift of a single crystal CaF_2 has been measured as a function of external pressure up to 4 kilobar at room temperature using multiple pulse NMR techniques. The pressure dependence of the shift is found to be -1.7 ± 1 ppm/kbar, while a theoretical calculation using an overlap model predicts a shift of -0.46 ppm/kbar. In the second section a separation of the chemical shift tensor into physically meaningful "geometrical" and "chemical" contributions is presented and a comparison of the proposed model calculations with recently reported data on hydroxyl proton chemical shift tensors demonstrates, that for this system, the geometrical portion accounts for the qualitative features of the measured tensors.

Part two of the thesis consists of a study of fluoride ion motion in β-PbF_2 doped with NaF by measurement of the ^(19)F transverse relaxation time (T_2), spin lattice relaxation time (T_1) and the spin lattice relaxation time in the rotating frame (T_(1r)). Measurements over the temperature range of -50°C to 160°C lead to activation energies for T_1, T_(1r) and T_2 of 0.205 ± 0.01, 0.29 + 0.02 and 0.27 ± 0.01 ev/ion, and a T_(1r) minimum at 56°C yields a correlation time of 0.74 μsec. Pressure dependence of T_1 and T_2 yields activation volumes of <0.2 cm^3/g-mole and 1.76 ± 0.05 cm^3/g-mole respectively. These data along with the measured magnetic field independence of T_1 suggest that the measured T_1's are not caused by ^(19)F motion, but by thermally excited carriers.

Part three of the thesis consists of a study of two samples of Th_4H_(15), prepared under different conditions but both having the proper ratio of H/Th (to within 1%). The structure of the Th_4H_(15) as suggested by X-ray measurements is confirmed through a moment analysis of the rigid lattice line shape. T_1 and T_2 measurements above 390 K furnish activation energies of 16.3 ± 1.2 kcal/mole and 18.0 ± 3.0 kcal/mole, respectively. Below 350 K, T_(1r) measurements furnish an activation energy of 10.9 ± 0.7 kcal/mole, indicating most probably more than a single mechanism for proton motion. A time-temperature hysteresis effect of the proton motion was found in one of the two samples and is strongly indicative of a phase change. T_1 at room temperature and below is dominated by relaxation due to conduction electrons with the product T_1T being 180 ± 10 K-sec. Using multiple pulse techniques to greatly reduce homonuclear dipolar broadening, a temperature-dependent line shift was observed, and the chemical shift anisotropy is estimated to be less than 16 ppm.

Study of the effect of alcohol on single human red blood cells using near-infrared laser tweezers Raman spectroscopy

The effect of alcohol solution on single human red blood Cells (RBCs) was investigated using near-infrared laser tweezers Raman spectroscopy (LTRS). In our system, a low-power diode laser at 785 nm was applied for the trapping of a living cell and the excitation of its Raman spectrum. Such a design could simultaneously reduce the photo-damage to the cell and suppress the interference from the fluorescence on the Raman signal. The denaturation process of single RBCs in 20% alcohol solution was investigated by detecting the time evolution of the Raman spectra at the single-cell level. The vitality of RBCs was characterized by the Raman band at 752 cm(-1), which corresponds to the porphyrin breathing mode. We found that the intensity of this band decreased by 34.1% over a period of 25 min after the administration of alcohol. In a further study of the dependence of denaturation on alcohol concentration, we discovered that the decrease in the intensity of the 752 cm(-1) band became more rapid and more prominent as the alcohol concentration increased. The present LTRS technique may have several potential applications in cell biology and medicine, including probing dynamic cellular processes at the single cell level and diagnosing cell disorders in real time. Copyright (c) 2005 John Wiley T Sons, Ltd.

Diseño y despliegue de una red inalámbrica segura y control de acceso de sensores IP

[ES]El proyecto está orientado a conseguir una comunicación inalámbrica y segura de una red de sensores IP. Por un lado, mediante el protocolo 6LoWPAN se consigue que los datos se transmitan mediante IPv6 y, por otro lado, gracias al protocolo LADON se establecen los servicios de seguridad de autenticación, integridad de datos, autorización y control de acceso.

Computationally Guided Monomerization of Red Fluorescent Proteins of the Class Anthozoa

Red fluorescent proteins (RFPs) have attracted significant engineering focus because of the promise of near infrared fluorescent proteins, whose light penetrates biological tissue, and which would allow imaging inside of vertebrate animals. The RFP landscape, which numbers ~200 members, is mostly populated by engineered variants of four native RFPs, leaving the vast majority of native RFP biodiversity untouched. This is largely due to the fact that native RFPs are obligate tetramers, limiting their usefulness as fusion proteins. Monomerization has imposed critical costs on these evolved tetramers, however, as it has invariably led to loss of brightness, and often to many other adverse effects on the fluorescent properties of the derived monomeric variants. Here we have attempted to understand why monomerization has taken such a large toll on Anthozoa class RFPs, and to outline a clear strategy for their monomerization. We begin with a structural study of the far-red fluorescence of AQ143, one of the furthest red emitting RFPs. We then try to separate the problem of stable and bright fluorescence from the design of a soluble monomeric β-barrel surface by engineering a hybrid protein (DsRmCh) with an oligomeric parent that had been previously monomerized, DsRed, and a pre-stabilized monomeric core from mCherry. This allows us to use computational design to successfully design a stable, soluble, fluorescent monomer. Next we took HcRed, which is a previously unmonomerized RFP that has far-red fluorescence (λemission = 633 nm) and attempted to monomerize it making use of lessons learned from DsRmCh. We engineered two monomeric proteins by pre-stabilizing HcRed’s core, then monomerizing in stages, making use of computational design and directed evolution techniques such as error-prone mutagenesis and DNA shuffling. We call these proteins mGinger0.1 (λem = 637 nm / Φ = 0.02) and mGinger0.2 (λem = 631 nm Φ = 0.04). They are the furthest red first generation monomeric RFPs ever developed, are significantly thermostabilized, and add diversity to a small field of far-red monomeric FPs. We anticipate that the techniques we describe will be facilitate future RFP monomerization, and that further core optimization of the mGingers may allow significant improvements in brightness.

Mechanism of red colouration in Tovel-See (”Conclusions” only) [Translation from: Archiv fur Hydrobiologie 38 299-302, 1941]

Cases of red colouration in small lake basins, due to the abundant appearance of microorganisms have long been known. Usually it is caused by a fast, sudden, intensive propagation (so called ”bloom”) of Cyanophycae and bacteria. (e.g. Oscillatoracae, thiobacteria etc.). An exception to this is the red colouration of Tovel-See, an alpine lake basin in the Dolomites of the Brenta group (Trentino), lying at a height of 1178 m and hidden in the woodland of a valley. Here the red bloom has a double rhythm: a daily and a yearly rhythm. The colouration of one part of the lake takes place in the warmest months of the year (i.e. July, August, September) and in the middle hours of the day. The immediate origin of the bloom has been known for a long time: it is caused by the Peridinacae Glenodinium sanguineum. This paper describes the phenomenon of red colouration of the lake and discusses its conditions.

Diseño de un detector para una red de vigilancia radiológica ambiental

[ES]El objetivo de este trabajo es analizar el montaje de un contador proporcional de radiación para su uso en una red de vigilancia radiológica ambiental desde su diseño básico hasta su puesta en marcha. Se realizará un análisis de las razones que nos han llevado a elegir este tipo de contadores de ionización gaseosa (frente a otros tipos), para llegar a la conclusión de que son los más adecuados para la vigilancia radiológica ambiental. Este análisis describirá la solución a la que se ha llegado para construir un contador con los medios al alcance y el porqué de su diseño concreto, así como la metodología de trabajo que se ha seguido para la obtención del mismo. Basándonos en suposiciones teóricas derivadas del análisis geométrico de la instrumentación para la obtención de resultados previsibles, se realizará una verificación mediante ensayos técnicos en el laboratorio. Se presupuestará el material utilizado y las horas requeridas, para llevar una cuenta de lo que le ha costado al departamento y lo que le habría costado en caso de no poseer la instrumentación utilizada. Después de realizar diversos test relacionados con la instrumentación electrónica, se procederá a obtener unas conclusiones derivadas de los ensayos en el laboratorio para su posterior comparación con las estimaciones teóricas. En el anexo I se encuentran los planos de diseño que se han realizado y en el anexo II los resultados finales obtenidos de los ensayos.