The relationship between otolith increments and time for yellowfin and skipjack tuna marked with tetracycline

ENGLISH: The rate at which increments are deposited on the sagittal otoliths of yellowfin (Thunnus albacares) and skipjack (Katsuwonus p elamis) tunas is determined by a markrecapture experiment using tetracycline. During growth in fork length from 40 to 110 em, and for a period of up to 389 days, yellowfin of the Revillagigedo Islands- Baja California region deposit one increment per day in either the postrostrum or rostrum position of the otolith. For skipjack of the same region, rostrum increments underestimate time by approximately 24 percent during growth from 42 to 64 cm and over the maximum interval of 249 days. The growth rate of each species is estimated from the recapture fork length and the linear change in an otolith dimension following tetracycline injection. Over specific ranges in fork length the rates are 3.06 and 1.15 em per month for yellowfin and skipjack, respectively. SPANISH: La rapidez (tasa) en la que se depositan los incrementos en los otolitos sagitales del aleta amarilla (Thunnus albacares) y el barrilete (Katsuwonus pelamis) se determina mediante un experimento al recapturar los peces que han sido marcados con tetraciclina. Durante el crecimiento de la longitud de horquilla de 40 a 110 cm y por un período hasta de 389 días, se forma en el aleta amarilla de la región de las Islas Revillagigedo-Baja California, un incremento diario ya sea en el parte del postrostrum o rostrum de los otolitos. Con respecto al barrilete de la misma region los incrementos en el rostrum subestiman aproximadamente el tiempo en un 24 por ciento durante el crecimiento de 42 a 64 cm y sobre un intervalo máximo de 249 días. El índice de crecimiento de cada especie se estima en la recaptura según la longitud de horquilla y el cambio lineal en la dimensión de un otolito después de la inyección de tetraciclina. La variación específica sobre la longitud de horquilla de los índices son 3.06 y 1.15 cm por mes para el aleta amarilla y el barrilete, respectivamente. (PDF contains 54 pages.)

Length-weight relationship and organ indices of pond raised and wild population of C. gariepinus (Burchell 1822) pisces-Claridae

Samples of C. gariepinus collected from the wild and cultured populations in Plateau and Niger States of Nigeria were analyzed for length-weight relationship and organ indices (Gonadosomatic index (GSI), hepatosomatic index (HSI), renalsomatic index (RSI) and somatic fat deposit index (PDI). High correlation and linear relationship between body length and body weight was observed in all sample population (P<0.05). A significant difference was observed between the GSI of males and females of both wild and cultured population and also between females of the wild and cultured population,(P < 0.05).There was no significant difference in HSI, CSI RSI and PDI of all the sample populations (P < 0.05).The importance of length-weight relationship and organ indices in fish production are discussed

A plasma channel scheme for the interaction of an intense femtosecond laser pulse with a deuterium cluster jet

We propose a plasma channel scheme to obtain an improved table-top laser driven fusion neutron yield as a result of explosions of large deuterium clusters irradiated by an intense laser pulse. A cylindrical plasma channel is created by two moderate intensity laser prepulses at the edge of a deuterium cluster jet along which an intense main laser pulse propagates several nanoseconds later. With the aid of this plasma channel, the main laser pulse will be allowed to deposit its energy into the central region of the deuterium gas jet where the cluster sizes are larger and the atomic density is higher. The plasma channel formation and its impact on the deuterium ion energy spectrum and the consequent fusion neutron yield have been investigated. The calculated results show that a remarkable increase of the table-top laser driven fusion neutron yield would be expected.

Mechanism study of femtosecond laser induced selective metallization (FLISM) on glass surfaces

We investigate the mechanism of selective metallization on glass surfaces with the assistance of femtosecond laser irradiation followed by electroless plating. Irradiation of femtosecond laser makes it possible to selectively deposit copper microstructures in the irradiated area on glass surfaces coated with silver nitrate films. The energy-dispersive X-ray (EDX) analyses reveal that silver atoms are produced on the surface of grooves formed by laser ablation, which serve as catalysis seeds for subsequent electroless copper plating. (C) 2008 Elsevier B.V. All rights reserved.

Dating and characterizing late holocene earthquakes using paleomagnetics

In this thesis I apply paleomagnetic techniques to paleoseismological problems. I investigate the use of secular-variation magnetostratigraphy to date prehistoric earthquakes; I identify liquefaction remanent magnetization (LRM), and I quantify coseismic deformation within a fault zone by measuring the rotation of paleomagnetic vectors.

In Chapter 2 I construct a secular-variation reference curve for southern California. For this curve I measure three new well-constrained paleomagnetic directions: two from the Pallett Creek paleoseismological site at A.D. 1397-1480 and A.D. 1465-1495, and one from Panum Crater at A.D. 1325-1365. To these three directions I add the best nine data points from the Sternberg secular-variation curve, five data points from Champion, and one point from the A.D. 1480 eruption of Mt. St. Helens. I derive the error due to the non-dipole field that is added to these data by the geographical correction to southern California. Combining these yields a secular variation curve for southern California covering the period A.D. 670 to 1910, with the best coverage in the range A.D. 1064 to 1505.

In Chapter 3 I apply this curve to a problem in southern California. Two paleoseismological sites in the Salton trough of southern California have sediments deposited by prehistoric Lake Cahuilla. At the Salt Creek site I sampled sediments from three different lakes, and at the Indio site I sampled sediments from four different lakes. Based upon the coinciding paleomagnetic directions I correlate the oldest lake sampled at Salt Creek with the oldest lake sampled at Indio. Furthermore, the penultimate lake at Indio does not appear to be present at Salt Creek. Using the secular variation curve I can assign the lakes at Salt Creek to broad age ranges of A.D. 800 to 1100, A.D. 1100 to 1300, and A.D. 1300 to 1500. This example demonstrates the large uncertainties in the secular variation curve and the need to construct curves from a limited geographical area.

Chapter 4 demonstrates that seismically induced liquefaction can cause resetting of detrital remanent magnetization and acquisition of a liquefaction remanent magnetization (LRM). I sampled three different liquefaction features, a sandbody formed in the Elsinore fault zone, diapirs from sediments of Mono Lake, and a sandblow in these same sediments. In every case the liquefaction features showed stable magnetization despite substantial physical disruption. In addition, in the case of the sandblow and the sandbody, the intensity of the natural remanent magnetization increased by up to an order of magnitude.

In Chapter 5 I apply paleomagnetics to measuring the tectonic rotations in a 52 meter long transect across the San Andreas fault zone at the Pallett Creek paleoseismological site. This site has presented a significant problem because the brittle long-term average slip-rate across the fault is significantly less than the slip-rate from other nearby sites. I find sections adjacent to the fault with tectonic rotations of up to 30°. If interpreted as block rotations, the non-brittle offset was 14.0+2.8, -2.1 meters in the last three earthquakes and 8.5+1.0, -0.9 meters in the last two. Combined with the brittle offset in these events, the last three events all had about 6 meters of total fault offset, even though the intervals between them were markedly different.

In Appendix 1 I present a detailed description of my standard sampling and demagnetization procedure.

In Appendix 2 I present a detailed discussion of the study at Panum Crater that yielded the well-constrained paleomagnetic direction for use in developing secular variation curve in Chapter 2. In addition, from sampling two distinctly different clast types in a block-and-ash flow deposit from Panum Crater, I find that this flow had a complex emplacement and cooling history. Angular, glassy "lithic" blocks were emplaced at temperatures above 600° C. Some of these had cooled nearly completely, whereas others had cooled only to 450° C, when settling in the flow rotated the blocks slightly. The partially cooled blocks then finished cooling without further settling. Highly vesicular, breadcrusted pumiceous clasts had not yet cooled to 600° C at the time of these rotations, because they show a stable, well clustered, unidirectional magnetic vector.

Wind-driven desertification: process modeling, remote monitoring, and forecasting

Arid and semiarid landscapes comprise nearly a third of the Earth's total land surface. These areas are coming under increasing land use pressures. Despite their low productivity these lands are not barren. Rather, they consist of fragile ecosystems vulnerable to anthropogenic disturbance.

The purpose of this thesis is threefold: (I) to develop and test a process model of wind-driven desertification, (II) to evaluate next-generation process-relevant remote monitoring strategies for use in arid and semiarid regions, and (III) to identify elements for effective management of the world's drylands.

In developing the process model of wind-driven desertification in arid and semiarid lands, field, remote sensing, and modeling observations from a degraded Mojave Desert shrubland are used. This model focuses on aeolian removal and transport of dust, sand, and litter as the primary mechanisms of degradation: killing plants by burial and abrasion, interrupting natural processes of nutrient accumulation, and allowing the loss of soil resources by abiotic transport. This model is tested in field sampling experiments at two sites and is extended by Fourier Transform and geostatistical analysis of high-resolution imagery from one site.

Next, the use of hyperspectral remote sensing data is evaluated as a substantive input to dryland remote monitoring strategies. In particular, the efficacy of spectral mixture analysis (SMA) in discriminating vegetation and soil types and detennining vegetation cover is investigated. The results indicate that hyperspectral data may be less useful than often thought in determining vegetation parameters. Its usefulness in determining soil parameters, however, may be leveraged by developing simple multispectral classification tools that can be used to monitor desertification.

Finally, the elements required for effective monitoring and management of arid and semiarid lands are discussed. Several large-scale multi-site field experiments are proposed to clarify the role of wind as a landscape and degradation process in dry lands. The role of remote sensing in monitoring the world's drylands is discussed in terms of optimal remote sensing platform characteristics and surface phenomena which may be monitored in order to identify areas at risk of desertification. A desertification indicator is proposed that unifies consideration of environmental and human variables.

Manganese: Minerals, Microbes, and the Evolution of Oxygenic Photosynthesis

Oxygenic photosynthesis fundamentally transformed our planet by releasing molecular oxygen and altering major biogeochemical cycles, and this exceptional metabolism relies on a redox-active cubane cluster of four manganese atoms. Not only is manganese essential for producing oxygen, but manganese is also only oxidized by oxygen and oxygen-derived species. Thus the history of manganese oxidation provides a valuable perspective on our planet’s environmental past, the ancient availability of oxygen, and the evolution of oxygenic photosynthesis. Broadly, the general trends of the geologic record of manganese deposition is a chronicle of ancient manganese oxidation: manganese is introduced into the fluid Earth as Mn(II) and it will remain only a trace component in sedimentary rocks until it is oxidized, forming Mn(III,IV) insoluble precipitates that are concentrated in the rock record. Because these manganese oxides are highly favorable electron acceptors, they often undergo reduction in sediments through anaerobic respiration and abiotic reaction pathways.

The following dissertation presents five chapters investigating manganese cycling both by examining ancient examples of manganese enrichments in the geologic record and exploring the mineralogical products of various pathways of manganese oxide reduction that may occur in sediments. The first chapter explores the mineralogical record of manganese and reports abundant manganese reduction recorded in six representative manganese-enriched sedimentary sequences. This is followed by a second chapter that further analyzes the earliest significant manganese deposit 2.4 billon years ago, and determines that it predated the origin of oxygenic photosynthesis and thus is supporting evidence for manganese-oxidizing photosynthesis as an evolutionary precursor prior to oxygenic photosynthesis. The lack of oxygen during this early manganese deposition was partially established using oxygen-sensitive detrital grains, and so a third chapter delves into what these grains mean for oxygen constraints using a mathematical model. The fourth chapter returns to processes affecting manganese post-deposition, and explores the relationships between manganese mineral products and (bio)geochemical reduction processes to understand how various manganese minerals can reveal ancient environmental conditions and biological metabolisms. Finally, a fifth chapter considers whether manganese can be mobilized and enriched in sedimentary rocks and determines that manganese was concentrated secondarily in a 2.5 billion-year-old example from South Africa. Overall, this thesis demonstrates how microbial processes, namely photosynthesis and metal oxide-reducing metabolisms, are linked to and recorded in the rich complexity of the manganese mineralogical record.

Secondary Organic Aerosol Composition Studies Using Mass Spectrometry

Trace volatile organic compounds emitted by biogenic and anthropogenic sources into the atmosphere can undergo extensive photooxidation to form species with lower volatility. By equilibrium partitioning or reactive uptake, these compounds can nucleate into new aerosol particles or deposit onto already-existing particles to form secondary organic aerosol (SOA). SOA and other atmospheric particulate matter have measurable effects on global climate and public health, making understanding SOA formation a needed field of scientific inquiry. SOA formation can be done in a laboratory setting, using an environmental chamber; under these controlled conditions it is possible to generate SOA from a single parent compound and study the chemical composition of the gas and particle phases. By studying the SOA composition, it is possible to gain understanding of the chemical reactions that occur in the gas phase and particle phase, and identify potential heterogeneous processes that occur at the surface of SOA particles. In this thesis, mass spectrometric methods are used to identify qualitatively and qualitatively the chemical components of SOA derived from the photooxidation of important anthropogenic volatile organic compounds that are associated with gasoline and diesel fuels and industrial activity (C12 alkanes, toluene, and o-, m-, and p-cresols). The conditions under which SOA was generated in each system were varied to explore the effect of NO_x and inorganic seed composition on SOA chemical composition. The structure of the parent alkane was varied to investigate the effect on the functionalization and fragmentation of the resulting oxidation products. Relative humidity was varied in the alkane system as well to measure the effect of increased particle-phase water on condensed-phase reactions. In all systems, oligomeric species, resulting potentially from particle-phase and heterogeneous processes, were identified. Imines produced by reactions between (NH₄)₂SO₄ seed and carbonyl compounds were identified in all systems. Multigenerational photochemistry producing low- and extremely low-volatility organic compounds (LVOC and ELVOC) was reflected strongly in the particle-phase composition as well.

Tecnologia mais limpa aplicada ao tratamento de água em sistemas de resfriamento abertos com recirculação

Os estudos destinados à aplicação de uma tecnologia mais limpa ao tratamento de águas em sistemas de resfriamento abertos com recirculação resultaram no desenvolvimento de uma filosofia de tratamento baseada na busca de uma operação com ciclo de concentração ideal. Assim, por meio do controle do balanço material no sistema de resfriamento, seria alcançado um nível de concentração em que a água de circulação apresentaria, naturalmente e ao mesmo tempo, baixa tendência à corrosão do ferro e baixa tendência à formação de incrustação de carbonato de cálcio. O tratamento com inibidores de corrosão e de formação de depósitos seria apenas complementar e, conseqüentemente, reduzido o emprego de produtos químicos para o condicionamento da água. O presente trabalho procura demonstrar que o critério de tratamento baseado apenas no índice de estabilidade não leva em conta o fato de que as espécies solúveis em água não se concentram de uma mesma forma, principalmente como decorrência de reações de conversão envolvendo o íon bicarbonato e de precipitação do íon cálcio. Como suporte desse trabalho, foram realizados ensaios de campo em um sistema de resfriamento aberto com recirculação em operação normal, porém sem tratamento químico da água. Foi possível, desse modo, observar a variação da concentração de cada espécie crítica presente na água com a vazão de descarga efetuada. Os resultados obtidos e o estudo realizado mostram que a metodologia tradicional pode apresentar desvios da realidade que podem comprometer a qualidade do tratamento, obrigando o emprego de maiores concentrações de produtos químicos para condicionamento da água, contrariando, assim, o próprio propósito original de execução de um tratamento dentro dos princípios de uma produção mais limpa. Este trabalho procura, ainda, salientar a importância qualitativa e quantitativa das espécies presentes, na água de reposição, na qualidade do tratamento, alertando que o emprego de reúso de água, como reposição de um sistema de resfriamento, deve ser criteriosamente analisado, pois uma água de má qualidade pode tornar o tratamento interno impraticável, exigindo a execução de um tratamento prévio muitas vezes inviável do ponto de vista econômico e causador de impacto ambiental

Absolute oscillator strengths for iron, copper, cadmium and gold measured by the atomic beam method

Absolute f-values for 7 transitions in the first spectra of 4 elements have been measured using the atomic beam absorption technique. The equivalent widths of the absorption lines are measured with a photoelectric scanner and the atomic beam density is determined by continuously weighing a part of it with a sensitive automatic microbalance. The complete theory is presented and corrections are calculated to cope with gas absorption by the deposit on the microbalance pan and atoms which do not stick to the pan. An additional correction for the failure of the assumption of effusive flow in the formation of the atomic beam at large densities has been measured experimentally.

The following f-values were measured:

Fe: f_λ3720 = 0.0430 ± 8%

Cu: f_λ3247 = 0.427 ± 4.5%, f_λ3274 = 0.206 ± 4.7%, f_λ2492 = 0.0037 ± 9%

Cd: f_λ3261 = 0.00190 ± 7%, f_λ2288 = 1.38 ± 12%

Au: f_λ2428 = 0.283 ± 5.3%

Comparison with other accurately measured f-values, where they exist, shows agreement within experimental errors.

Metallogenic Provinces of the Southwestern United States and Northern Mexico

Some of the metallogenic provinces of the southwestern United States and northern Mexico are defined by the geographic distribution of trace elements in the primary sulfide minerals chalcopyrite and sphalerite. The elements investigated include antimony, arsenic, bismuth, cadmium, cobalt, gallium, germanium, indium, manganese, molybdenum, nickel, silver, tellurium, thallium, and tin. Of these elements, cobalt, gallium, germanium, indium, nickel, silver, and tin exhibit the best defined geographic distribution.

The data indicate that chalcopyrite is the preferred host for tin and perhaps molybdenum; sphalerite is the preferred host for cadmium, gallium, germanium, indium, and manganese; galena is the preferred host for antimony, bismuth, silver, tellurium, and thallium; and pyrite is the preferred host for cobalt, nickel, and perhaps arsenic. With respect to the two minerals chalcopyrite and sphalerite, antimony, arsenic, molybdenum, nickel, silver, and tin prefer chalcopyrite; and bismuth, cadmium, cobalt, gallium, germanium, indium, manganese, and thallium prefer sphalerite. This distribution probably is the result of the interaction of several factors, among which are these: the various radii of the elements, the association due to chemical similarities of the major and trace elements, and the degree of ionic versus covalent and metallic character of the metal-sulfur bonds in chalcopyrite and sphalerite. The type of deposit, according to a temperature classification, appears to be of minor importance in determining the trace element content of chalcopyrite and sphalerite.

A preliminary investigation of large single crystals of sphalerite and chalcopyrite indicates that the distribution within a single crystal of some elements such as cadmium in sphalerite and indium and silver in chalcopyrite is relatively uniform, whereas the distribution of some other elements such as cobalt and manganese in sphalerite is somewhat less uniform and the distribution of tin in sphalerite is extremely erratic. The variations in trace element content probably are due largely to variations in the composition of the fluids during the growth of the crystals, but the erratic behavior of tin in sphalerite perhaps is related to the presence of numerous cavities and inclusions in the crystal studied.

Maps of the geographic distribution of trace elements in chalcopyrite and sphalerite exhibit three main belts of greater than average trace element content, which are called the Eastern, Central, and Western belts. These belts are consistent in trend and position with a beltlike distribution of copper, gold, lead, zinc, silver, and tungsten deposits and with most of the major tectonic features. However, there appear to be no definite time relationships, for as many as four metallogenic epochs, from Precambrian to late Tertiary, are represented by ore deposits within the Central belt.

The evidence suggests that the beltlike features have a deep seated origin, perhaps in the sub-crust or outer parts of the mantle, and that the deposits within each belt might be genetically related through a beltlike compositional heterogeneity in the source regions of the ores. Hence, the belts are regarded as metallogenic provinces.

Análise de cobertura de metal-metal por XRF

A proposta do referente estudo foi medir a espessura do depósito de um metal em outro metal base, ou seja, utilizar o processo eletroquímico de Galvanoplastia ou eletrodeposição deste metal, por meio da técnica de fluorescência de raios X (XRF). O uso desta técnica justificou-se pelo interesse em reduzir os custos excessivos durante o processo eletroquímico, bem como, minimizar as possíveis margens de erros para obter resultados satisfatórios nas medidas. Neste trabalho, incluíram-se as medidas da espessura do Níquel (Ni) e análises da intensidade de radiação incidentes e a radiação atenuante, em função da espessura dos elementos Cromo (Cr) e Zinco (Zn), considerando como metal base o elemento Ferro (Fe). Em decorrência disso, em todos os casos foram simulados os processos de deposição do metal onde foram incluídos os resultados de absorção de raios X, além de desprezar a influência de outros fatores como a temperatura, o pH, o tratamento de superfície, entre outros, os quais são necessários para considerar em cada caso.

Elements of Decision under Uncertainty with Applications

This work presents the basic elements for the analysis of decision under uncertainty: Expected Utility Theory and its citicisms and risk aversion and its measurement. The concepts of certainty equivalent, risk premium, absolute risk aversion and relative risk aversion, and the "more risk averse than" relation are discussed. The work is completed with several applications of decision making under uncertainty to different economic problems: investment in risky assets and portfolio selection, risk sharing, investment to reduce risk, insurance, taxes and income underreporting, deposit insurance and the value of information.

Avaliação do potencial gerador da formação Tremembé, bacia de Taubaté, área de Pindamonhangaba e Moreira César-SP

O presente estudo aborda a caracterização faciológica e quimioestratigráfica do intervalo de folhelhos betuminosos da Formação Tremembé (Oligoceno da Bacia de Taubaté), bem como a avaliação econômica desses depósitos na região de Pindamonhangaba e Moreira César, SP. A partir da coleta sistemática de amostras de testemunhos do poço MOR-SP, foram determinados os teores de COT, S e RI, assim como dados de Pirólise Rock-Eval. Com base nesses dados seis unidades quimioestratigráficas(designadas de I a VI a partir da base) foram definidas no intervalo de cerca de 40 metros de espessura. Dados previamente estudados dos poços TMB-SP e PND-SP foram utilizados para correlação dessasunidades.Com base nos dados de Pirólise RockEval foi possível quantificar o volume de óleo potencialmente recuperável através do aproveitamento industrial dos folhelhos betuminosos. No intervalo mais promissor (unidades VI e V), compreendendo uma seção de cerca de 17 metros de espessura, o rendimento de óleo é de cerca de 25,7 milhões de barris por km2, na área do poço MOR-SP.Os dados obtidos apontam para uma importante jazida não convencional de folhelho betuminoso (oilshale), cujo aproveitamentoeconômico, se executado,requerirá, além de novas soluções tecnológicas, a implementação de ações de forma a minimizar os impactos sociais e ambientais de uma possível operação extrativa desse recurso.

Reproduction et fécondité du machoiron Chrysichthys nigrodigitatus en élevage

Different rearing facilities (concrete tanks, pens and ponds) were tested for suitability as spawning environments. The concrete tanks and the pens in the lagoon gave the best results as to the number of spawns obtained. Of the three types of spawning devices tested, containers with a 150 mm opening at one of the two ends were preferably used by the fish. The brooders in the spawning facilities spontaneously entered the spawning containers to deposit their eggs without external human intervention. Actual fecundity estimates ranged from 9805 to 40597.