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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Biological Productivity in the Northeast Pacific: Comparing an in-situ method with incubation based methods

Giesbrecht, Karina 29 October 2013 (has links)
In-situ net community production (NCP) was measured on nine cruises along Line P in the subarctic Northeast Pacific during 2007-2009 and incubation based new, regenerated and carbon production on four cruises starting in August 2008. In-situ NCP, determined using the O2/Ar gas ratio in the mixed layer, averaged 18.4±5.1 mmol O2 m-2 d-1 for stations west of 130°W in June and August. In-situ NCP was nearly equivalent to 24-h 15NO3 - based euphotic zone integrated new production (New-P) with an average NCP: New-P ratio of 1.3±0.4 that was consistent over a range of environmental conditions. The relationship between NCP and 24-h 13C integrated production (C-PP) was variable, but with a consistent mean NCP:C-PP ratio of 0.42±0.27 even when historical measurements were included in the comparison. Two offshore high productivity events were observed in the HNLC region of Line P, one centered between 134°W and 139°W and the other west of 130°W. Only one high productivity event shows conclusive evidence of being caused by iron deposition. / Graduate / 0416
2

Temporal variability of dissolved inorganic carbon at SEATS site:estimation of net community production (2002-2004)

Shih, Yung-Yen 27 June 2005 (has links)
Dissolved inorganic carbon (DIC), titration alkalinity (TA), and nitrate + nitrite (N+N) are measured from seasonal cruises at the time-series site SEATS in the northern South China Sea (18¢XN 116¢XE) between March 2002 and November 2004. The most distinctive feature of the annual nDIC (DIC normalized to a constant salinity of 33.8) cycle is an increase in wintertime and a decrease in summertime (March¡VAugust). The nDIC drawdown (-3.15 ¡Ó 2.23 mmol m-2 day-1) at summertime is mainly attributed to biological uptake of DIC. The other terms in the DIC budget calculation, i.e. the carbon fluxes of air-sea CO2 gas exchange, horizontal advection and vertical diffusion, are estimated to be -0.48 ¡Ó 0.31, -0.70 ¡Ó 0.86, and 2.50 ¡Ó 0.59 mmol m-2 day-1, respectively. Accordingly, results from the DIC budget calculation reveals a net community production (NCP) of -4.47 ¡Ó 1.98 mmol m-2 day-1. This calculated NCP from our data is in good agreement with the export and new production previously reported in the South China Sea. The consistency demonstrates that carbon system is almost in a steady state during summertime at SEATS. According to the Refield C : N ratio of 106 : 16, a flux of 0.67 ¡Ó 0.30 mmol m-2 day-1 of bioavailable nitrogen (Nbio) is needed to sustain the calculated NCP. The source terms in the Nbio budget calculation, i.e. the nitrogen fluxes of vertical diffusion, wet deposition, dry deposition and the contribution from the putative nitrogen-fixing cyanobacteria Trichodesmium and Richelia intra., are estimated to be 0.20 ¡Ó 0.04, 0.03 ¡Ó 0.01, 0.04 ~ 0.08, and 0.02 ~ 0.13 mmol m-2 day-1, respectively. It thus seems that all the source terms can only collectively account for 50 ~ 70% Nbio needed to support the estimated NCP. With this regard, unicellular cyanobacteria, which have been reported as an important N2-fixer in the subtropical North Pacific and identified by the nitrogenase genes (nifH) in the small size (less than 10
3

QUANTUM ERROR CORRECTION FOR GENERAL NOISE

Gonzales, Alvin Rafer 01 June 2021 (has links)
Large quantum computers have the potential to vastly outperform any classical computer. The biggest obstacle to building quantum computers of such size is noise. For example, state of the art superconducting quantum computers have average decoherence (loss of information) times of just microseconds. Thus, the field of quantum error correction is especially crucial to progress in the development of quantum technologies. In this research, we study quantum error correction for general noise, which is given by a linear Hermitian map. In standard quantum error correction, the usual assumption is to constrain the errors to completely positive maps, which is a special case of linear Hermitian maps. We establish constraints and sufficient conditions for the possible error correcting codes that can be used for linear Hermitian maps. Afterwards, we expand these sufficient conditions to cover a large class of general errors. These conditions lead to currently known conditions in the limit that the error map becomes completely positive. The later chapters give general results for quantum evolution maps: a set of weak repeated projective measurements that never break entanglement and the asymmetric depolarizing map composed with a not completely positive map that gives a completely positive composition. Finally, we give examples.
4

Multiple-respondent anecdotal assessments for behavior disorders; An analysis of interrater agreement and correspondence with treatment outcomes.

Wolf, Roxanne 05 1900 (has links)
The current study was designed to further evaluate the usefulness of anecdotal assessments. The goal of this study was to evaluate the overall agreement between multiple respondents on the primary function of aberrant behavior using the Motivation Assessment Scale (MAS) and the Functional Analysis Screening Tool (FAST) and, if agreement was obtained, to assess the effectiveness of treatment based on the outcome of the assessments. Results showed that anecdotal assessments were able to identify the general type of contingency maintaining two participants' problem behavior. However, for one participant the assessments did not correctly identify the specific form of reinforcement (attention or tangible items) that maintained the aberrant behavior.
5

An Internship with The Nature Conservancy's Northern Caribbean Program

Moss, Sharrah January 2012 (has links)
No description available.
6

Recognition and Probing of RNA Non-canonical Pair (NCP) Site Enabled by Triplex Hybridization with Bifacial Peptide Nucleic Acids (bPNA)

Tang, Xue 21 July 2022 (has links)
No description available.
7

Produção de insumos para o imunodiagnóstico da neosporose / Development of immunochemical assays for the immunodiagnosis of neosporosis

Pacheco, Diene de Borba 21 February 2014 (has links)
Made available in DSpace on 2014-08-20T14:31:31Z (GMT). No. of bitstreams: 1 dissertacao_diene_de_borba_pacheco.pdf: 1130271 bytes, checksum: e77a03d669b55e89749bb0d6922531eb (MD5) Previous issue date: 2014-02-21 / Neosporosis is a disease caused by the apicomplexan parasite Neospora caninum, which is closely related to Toxoplasma gondii. N. caninum infection represents an important cause of reproductive failure in sheep, goats, horses, and cattle worldwide. The diagnosis of neosporosis is based on the detection of pathogen-specific antibodies in animal sera or the presence of tissue cysts. However, morphological similarities and serological cross-reactivity between N. caninum and T. gondii can result in the misdiagnosis. In this study, the N. caninum tachyzoite surface protein Ncp-43 was expressed in a recombinant form to elicit polyclonal antibodies (pAb) response. The pAb was purified and conjugated to horseradish peroxidase (HRP) or fluorescein isothiocyanate (FITC) to detect the recombinant and native Ncp-43 proteins, respectively. The pAb and pAb/HRP were able to recognize rNcp-43 by Dot blot and ELISA, and pAb/FITC immunolabeled the apical complex of tachyzoites. A blocking enzyme-linked immunosorbent assay (b-ELISA) was performed to evaluate pAb/HRP as a diagnostic tool. The mean percent inhibition for the positive and negative serum samples from cattle with neosporosis was significantly different (P < 0.0001). These results suggest that the pAb may bind to the same epitopes of Ncp-43 as anti-N. caninum antibodies in the positive samples tested. The b-ELISA using the pAb/HRP can facilitate diagnostic testing for neosporosis, since fewer steps are involved and cross-reactivity with secondary antibodies is avoided. In summary, this report describes the production of antibodies against N. caninum, and evaluates the potential of these tools for the development of new diagnostic tests for neosporosis. / Neosporose é a doença causada pelo parasito apicomplexa Neospora caninum, o qual é intimamente relacionado a Toxoplasma gondii. A infecção por N. caninum representa uma importante causa de falha reprodutiva em ovinos, caprinos, equinos e bovinos ao redor do mundo. O diagnóstico da neosporose é baseado na detecção de anticorpos específicos contra o patógeno em soros, ou a presença de cistos teciduais em animais. No entanto, as semelhanças morfológicas e a possível reatividade sorológica cruzada entre N. caninum e T. gondii pode resultar no diagnóstico errôneo. Neste estudo, a proteína de superfície Ncp-43 de taquizoítos de N. caninum, foi expressa de forma recombinante em Escherichia coli e utilizada para produção de anticorpos policlonais (pAb). O pAb foi purificado e conjugado a peroxidase (HRP) e isotiocianato de fluoresceína (FITC) para detectar as proteínas recombinantes e nativas Ncp-43, respectivamente. pAb e pAb/HRP foram capazes de reconhecer rNcp-43, o que foi avaliado pelas técnicas de Dot blot e ELISA enquanto pAb/FITC se mostrou eficiente na imunomarcação do complexo apical de taquizoítos. Um ensaio imunoenzimático de bloqueio (b-ELISA) foi realizado para avaliar a performance do pAb/HRP como ferramenta de diagnóstico. A porcentagem de inibição média para as amostras de pool de soros positivos e o pool de negativos de bovinos com neosporose foi significativamente diferente (P <0,0001). Estes resultados sugerem que o pAb pode ligar-se aos mesmos epítopos da Ncp-43 que os anticorpos anti-N. caninum de amostras positivas testadas. O b-ELISA utilizando o pAb/HRP representa uma opção interessante aos testes de diagnóstico disponíveis para a neosporose, uma vez que menos passos estão envolvidos na sua realização e seu formato evita a reatividade cruzada com anticorpos anti-espécie específicos. Em resumo, este trabalho descreve a produção de anticorpos contra N. caninum, e avalia o potencial dessas ferramentas para o desenvolvimento de novos testes diagnósticos para neosporose.
8

Programação em dois níveis: reformulação utilizando as condições KKT / Bilevel programming: reformulation using KKT conditions.

Sobral, Francisco Nogueira Calmon 22 February 2008 (has links)
Em um problema de natureza hierárquica, o nível mais influente toma certas decisões que afetam o comportamento dos níveis inferiores. Cada decisão do nível mais influente é considerada como fixa pelos níveis inferiores, que, com tais informações, tomam decisões que maximizam seus objetivos. Essas decisões podem influenciar os resultados obtidos pelo nível superior, que, por sua vez, também anseia pela decisão ótima. Em programação matemática, este problema é modelado como um problema de programação em níveis. Neste trabalho, consideramos uma classe particular de problemas de programação em níveis: os problemas de programação matemática em dois níveis. Estudamos uma técnica de resolução que consiste em substituir o problema do nível inferior por suas condições necessárias de primeira ordem, que podem ser formuladas de diversas maneiras, conforme as restrições de complementaridade são modificadas. O novo problema torna-se um problema de programação não linear e pode ser resolvido com algoritmos clássicos de otimização. Com o auxílio de condições de otimalidade de primeira e segunda ordem mostramos as relações entre o problema original e o problema reformulado. Aplicamos a técnica a problemas encontrados na literatura, analisamos o seu comportamento e apresentamos estratégias para eliminar certos inconvenientes encontrados. / In problems of hierarchical nature, the choices made by the most influential level - the so-called leader - affect the behavior of the lower levels. For each one of the leader\'s decisions there is a response from the lower levels, which maximizes the value of their respective objectives. These optimal choices, in return, may have influence in the results achieved by the leader, which also wants to make the optimal choices. In mathematical programming, this kind of problem is described as a multilevel programming problem. The present work considers a specific kind of multilevel problem: the bilevel mathematical problem. We study a resolution technique which consists in replacing the lower level problem by its necessary first order conditions, which can be formulated in various ways, as complementarity constraints occur and are modified. The new reformulated problem is a nonlinear programming problem which can be solved by classical optimization methods. Using first and second order optimality conditions, we show the relations between the original bilevel problem and the reformulated problem. We apply the described technique to solve a set of bilevel problems taken from the literature, analyse their behavior and discuss strategies to prevent undesirable difficulties that may arise.
9

Programação em dois níveis: reformulação utilizando as condições KKT / Bilevel programming: reformulation using KKT conditions.

Francisco Nogueira Calmon Sobral 22 February 2008 (has links)
Em um problema de natureza hierárquica, o nível mais influente toma certas decisões que afetam o comportamento dos níveis inferiores. Cada decisão do nível mais influente é considerada como fixa pelos níveis inferiores, que, com tais informações, tomam decisões que maximizam seus objetivos. Essas decisões podem influenciar os resultados obtidos pelo nível superior, que, por sua vez, também anseia pela decisão ótima. Em programação matemática, este problema é modelado como um problema de programação em níveis. Neste trabalho, consideramos uma classe particular de problemas de programação em níveis: os problemas de programação matemática em dois níveis. Estudamos uma técnica de resolução que consiste em substituir o problema do nível inferior por suas condições necessárias de primeira ordem, que podem ser formuladas de diversas maneiras, conforme as restrições de complementaridade são modificadas. O novo problema torna-se um problema de programação não linear e pode ser resolvido com algoritmos clássicos de otimização. Com o auxílio de condições de otimalidade de primeira e segunda ordem mostramos as relações entre o problema original e o problema reformulado. Aplicamos a técnica a problemas encontrados na literatura, analisamos o seu comportamento e apresentamos estratégias para eliminar certos inconvenientes encontrados. / In problems of hierarchical nature, the choices made by the most influential level - the so-called leader - affect the behavior of the lower levels. For each one of the leader\'s decisions there is a response from the lower levels, which maximizes the value of their respective objectives. These optimal choices, in return, may have influence in the results achieved by the leader, which also wants to make the optimal choices. In mathematical programming, this kind of problem is described as a multilevel programming problem. The present work considers a specific kind of multilevel problem: the bilevel mathematical problem. We study a resolution technique which consists in replacing the lower level problem by its necessary first order conditions, which can be formulated in various ways, as complementarity constraints occur and are modified. The new reformulated problem is a nonlinear programming problem which can be solved by classical optimization methods. Using first and second order optimality conditions, we show the relations between the original bilevel problem and the reformulated problem. We apply the described technique to solve a set of bilevel problems taken from the literature, analyse their behavior and discuss strategies to prevent undesirable difficulties that may arise.
10

Modelling oxygen and argon to improve estimation of net community productivity in a coastal upwelling zone using ∆O2/Ar

Teeter, Lianna 24 December 2014 (has links)
Under steady state conditions where the rate of biological oxygen production is balanced by oxygen evasion to the atmosphere, net community production (NCP) can be estimated from mixed layer oxygen/argon measurements. This method is effective in the open ocean but not in coastal zones where upwelling of low oxygen water violates the simple steady state assumption. Since these upwelling regions are highly productive, excluding them can lead to significant underestimations of global productivity. Here, I use a quasi-2D version of the Regional Ocean Modelling System (ROMS), including oxygen and argon as prognostic variables, to model the relationship between NCP and the sea-to-air flux of biological oxygen in a coastal upwelling system. The relationship between the sea-to-air flux of biological oxygen and NCP is poorest near the shore during upwelling favourable winds when waters that are undersaturated in oxygen reach the surface and depress the oxygen/argon ratio. I averaged NCP temporally and spatially over the residence time with respect to gas exchange and the Lagrangian motion of a water parcel. I found that the maximum distance travelled (∼25 km) over this time period indicated a distance from the upwelling plume at which much of the the low oxygen signal is erased. When the sea-to-air flux of biological oxygen was below 20 mmol m−2 day−1, NCP was usually also found in that range. Above that range the sea-to-air flux of biological oxygen is a lower bound for NCP. NCP occurring below the mixed layer can affect the sea-to-air flux of biological oxygen either by entrainment or diffusion into the mixed layer causing an overestimation of NCP, but this process had a minimal effect on most of my model data. Removing values with mixed layers deeper than 25 m improves the estimation, although further studies may reveal that this depth should be adjusted based on mean wind forcing. / Graduate / 0415

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