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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.
161

CARD-BASEDTELEMETRY RECEIVERS

Porter, Jim, Meyers, Tom 10 1900 (has links)
International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / Embedded "Card-Based" receivers are one of the latest innovations in telemetry reception. These products provide substantial power and flexibility in a small form factor (one slot, PC or VME). In many applications they are a cost effective alternative to conventional telemetry receivers. This paper analyzes currently available products with regard to their features, capabilities, and performance, as well as highlighting typical applications.
162

Genetic analysis of nitrogen assimilation in the Texas brown tide Aureoumbra lagunensis

Agostoni, Marco 26 October 2010 (has links)
The initiation, persistence, and termination of harmful algal blooms (HABs) can all be influenced by nutrient availability. Recent studies have highlighted the role of both organic and inorganic nitrogen sources in HAB dynamics. The pelagophyte Aureoumbra lagunensis causes ecosystem disruptive algal blooms and is responsible for the longest recorded harmful algal bloom (1989-1997). Because of Aureoumbra's small size and its inability to use nitrate, it has been hypothesized that its ability to use ammonium and organic nitrogen, especially at low concentrations, contributed to the unusual persistence of this bloom. This project aimed to assess the response of Aureoumbra to inorganic and organic nitrogen sources by examining the expression of genes responsible for nitrogen assimilation, with an eventual intent of developing expression assays that are indicative of nitrogen source use and/or sufficiency in Aureoumbra. Large volume batch cultures of Aureoumbra were grown with either ammonium or urea as a nitrogen source. Physiological characteristics (C:N, chlorophyll [alpha] cell⁻¹, and Fv/Fm) were monitored throughout the growth period, and the expression of the AMT-1, AMT-2 and UREC genes was assayed at early-, mid- and late-exponential phases. The results show that Aureoumbra can use both ammonium and urea, and that it is well adapted to low-nutrient environments. Only one gene, AMT-1, appeared to be transcriptionally regulated in response to changing nitrogen concentration, and only to ammonium. The results of this study contribute to our understanding of how algae in general cope with low nutrient availability and should ultimately help to define the dynamics of these HAB events. / text
163

Införandet av Multiplex Power-metodenför att kontrollera FM-deviationenvid radiosändningar inom Sverige

Elisejev, Svjatoslav, Stegman, Mikael January 2009 (has links)
<p>Detta examensarbete presenterar en utvärdering av konsekvenser som kan uppstå vid Införandet av Multiplex Power-mättmetoden för att kontrollera FM-deviation vid radiosändningar i Sverige.</p><p>Metoden är beskriven i en publicerad standard från ITU: ITU-R BS.412-9. Metoden, även kallad Multiplex Power, är en begränsningsstandard för analog (terrestrial) FM sändning på VHF band. Skälet att införa Multiplex Power mätning är att man genom metoden både kan minska grannkanalinterferenserna och samtidigt jämna ut de stora variationerna i de upplevda ljudnivåerna som finns mellan de olika FM-stationerna. Denna mätmetod går ut på att man samplar värden på deviation, lagrar samplen och räknar ut ett medelvärde av energin under ett intervall av 60 sekunder. Detta energivärde jämförs med en referensnivå, som i ITU-normen definieras som +/-19kHz toppdeviation vid 400 Hz modulationssignal. Skillnaden detta referensvärde kan anges i dB av instrumentet, som en enskild siffra vilkets värde skrivs dynamiskt över tid.</p><p>För att kunna utvärdera metoden genomfördes ett lyssningsexperiment. I experimentet användes ljudfiler som är processade enligt hur dagens normer tillämpas i Sverige och ljudfiler som är processade för att följa BS.412-9-normen. Som tillvägagångssätt användes ett webbformulär och en databas. Testpersoner kunde utföra lyssningen och notera resultatet som sedan lagrades för vidare beräkningar. Ljudfilerna och tillhörande mätningsvärden från lyssningsexperimentet användes sedan för att utvärdera resultatet.</p> / QC 20100707
164

Variantes do gene THPO em pacientes com anemia aplástica adquirida / THPO gene variants in patients with acquired aplastic anemia

Padilha, Pedro Henrique 09 January 2018 (has links)
Introdução: A anemia aplástica (AA) adquirida é uma doença grave, caracterizada por pancitopenia e medula óssea hipocelular sem que haja associação com aumento de reticulina ou infiltração anormal na medula. Embora o mecanismo fisiopatológico não esteja totalmente elucidado, atribui-se a uma resposta imunomediada dos linfócitos T no ambiente medular. A trombopoetina (codificada pelo gene THPO) é um hormônio glicoproteico produzido pelo fígado e responsável pelo estímulo de crescimento de megacariócitos, desenvolvimento plaquetário e de demais linhagens e, quando disfuncional, contribui para o desenvolvimento da AA adquirida. Objetivos: Investigar a presença de variantes genéticas no THPO em amostras de sangue periférico e medula óssea de pacientes com AA adquirida (grupo caso) e de indivíduos saudáveis (grupo controle) e verificar a presença de alterações no número de plaquetas durante o seguimento dos pacientes com AA adquirida. Métodos: O gene THPO foi sequenciado em amostras de DNA de medula óssea de 92 pacientes com AA adquirida e no DNA de sangue periférico de 92 controles, cujas amostras haviam sido previamente armazenado no Laboratório de Hematologia da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP). O sequenciamento foi realizado pelo método de Sanger. Realizou-se também a associação entre a presença (ou ausência) de variantes em THPO e o número de plaquetas em 83 pacientes utilizando o teste ANOVA Para outras análises estatísticas, foram utilizados os testes t e qui-quadrado com nível de significância de 5%. Resultados: Foram encontrados três polimorfismos de nucleotídeo único (SNPs) nos pacientes com AA adquirida (rs956732, rs6141 e rs3804618). Os mesmos três SNPs foram observados nos indivíduos do grupo controle (p>0,05). Não houve associação entre o número de plaquetas e a presença de SNPs nos pacientes (p>0,05). Conclusões: Três SNPs foram encontrados em frequências alélicas semelhantes tanto no grupo de pacientes quanto nos controles, sugerindo que a trombopoetina não apresenta alterações genéticas que possam ser associadas à fisiopatologia da AA adquirida nessa coorte. / Introduction: Acquired aplastic anemia (AA) is a severe illness, characterized by pancytopenia and hypocellular bone marrow without increased reticulin or abnormal infiltration of the bone marrow. Although the physiopathological mechanism has not been completely understood, an immune-mediated T-lymphocyte response has been attributed to the bone marrow environment. Thrombopoietin (encoded by THPO), a glycoprotein hormone produced by the liver and responsible for stimulating the growth of megakaryocytes, development of platelets and other lineages that when dysfunctional, contributes to the progress of acquired AA. Objectives: To screen the THPO gene for genetic variants in bone marrow of acquired AA patients and in the peripheral blood of controls, and to verify the correlation between the THPO status and platelet counts in the patients during the treatment. Method: Sanger sequencing of the THPO gene was carried out in 92 acquired AA patients (case group) and 92 controls, in DNA samples previously stored in the Hematology Laboratory of the Ribeirão Preto School of Medicine at the University of São Paulo. The association between the THPO status and the platelet counts was performed in 83 patients through the ANOVA test. The Chi-squared test and t-test were also applied for statistical analysis with a 5% significance level. Results: Three single nucleotide polymorphisms (SNPs) were found in the AA patients (rs956732, rs6141, and rs3804618), as well as in the healthy subjects (p>0,05). No association was verified between the platelet counts and the presence of SNPs in the AA patients (p>0,05). Conclusion: Three SNPs were found in both groups, suggesting that thrombopoietin does not harbor genetic variants that could be etiological for the acquired AA in our cohort.
165

Variantes do gene THPO em pacientes com anemia aplástica adquirida / THPO gene variants in patients with acquired aplastic anemia

Pedro Henrique Padilha 09 January 2018 (has links)
Introdução: A anemia aplástica (AA) adquirida é uma doença grave, caracterizada por pancitopenia e medula óssea hipocelular sem que haja associação com aumento de reticulina ou infiltração anormal na medula. Embora o mecanismo fisiopatológico não esteja totalmente elucidado, atribui-se a uma resposta imunomediada dos linfócitos T no ambiente medular. A trombopoetina (codificada pelo gene THPO) é um hormônio glicoproteico produzido pelo fígado e responsável pelo estímulo de crescimento de megacariócitos, desenvolvimento plaquetário e de demais linhagens e, quando disfuncional, contribui para o desenvolvimento da AA adquirida. Objetivos: Investigar a presença de variantes genéticas no THPO em amostras de sangue periférico e medula óssea de pacientes com AA adquirida (grupo caso) e de indivíduos saudáveis (grupo controle) e verificar a presença de alterações no número de plaquetas durante o seguimento dos pacientes com AA adquirida. Métodos: O gene THPO foi sequenciado em amostras de DNA de medula óssea de 92 pacientes com AA adquirida e no DNA de sangue periférico de 92 controles, cujas amostras haviam sido previamente armazenado no Laboratório de Hematologia da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP). O sequenciamento foi realizado pelo método de Sanger. Realizou-se também a associação entre a presença (ou ausência) de variantes em THPO e o número de plaquetas em 83 pacientes utilizando o teste ANOVA Para outras análises estatísticas, foram utilizados os testes t e qui-quadrado com nível de significância de 5%. Resultados: Foram encontrados três polimorfismos de nucleotídeo único (SNPs) nos pacientes com AA adquirida (rs956732, rs6141 e rs3804618). Os mesmos três SNPs foram observados nos indivíduos do grupo controle (p>0,05). Não houve associação entre o número de plaquetas e a presença de SNPs nos pacientes (p>0,05). Conclusões: Três SNPs foram encontrados em frequências alélicas semelhantes tanto no grupo de pacientes quanto nos controles, sugerindo que a trombopoetina não apresenta alterações genéticas que possam ser associadas à fisiopatologia da AA adquirida nessa coorte. / Introduction: Acquired aplastic anemia (AA) is a severe illness, characterized by pancytopenia and hypocellular bone marrow without increased reticulin or abnormal infiltration of the bone marrow. Although the physiopathological mechanism has not been completely understood, an immune-mediated T-lymphocyte response has been attributed to the bone marrow environment. Thrombopoietin (encoded by THPO), a glycoprotein hormone produced by the liver and responsible for stimulating the growth of megakaryocytes, development of platelets and other lineages that when dysfunctional, contributes to the progress of acquired AA. Objectives: To screen the THPO gene for genetic variants in bone marrow of acquired AA patients and in the peripheral blood of controls, and to verify the correlation between the THPO status and platelet counts in the patients during the treatment. Method: Sanger sequencing of the THPO gene was carried out in 92 acquired AA patients (case group) and 92 controls, in DNA samples previously stored in the Hematology Laboratory of the Ribeirão Preto School of Medicine at the University of São Paulo. The association between the THPO status and the platelet counts was performed in 83 patients through the ANOVA test. The Chi-squared test and t-test were also applied for statistical analysis with a 5% significance level. Results: Three single nucleotide polymorphisms (SNPs) were found in the AA patients (rs956732, rs6141, and rs3804618), as well as in the healthy subjects (p>0,05). No association was verified between the platelet counts and the presence of SNPs in the AA patients (p>0,05). Conclusion: Three SNPs were found in both groups, suggesting that thrombopoietin does not harbor genetic variants that could be etiological for the acquired AA in our cohort.
166

Image analysis and computational modelling of Activity-Dependent Bulk Endocytosis in mammalian central nervous system neurons

Stewart, Donal Patrick January 2017 (has links)
Synaptic vesicle recycling is the reuse of synaptic membrane material and proteins after vesicles have been exocytosed at the pre-synaptic terminal of a neuronal synapse. The discovery of the mechanisms by which recycling operates is a subject of active research. Within small mammalian central nervous system nerve terminals, two studied mechanisms of recovery are clathrin-mediated endocytosis and activity-dependent bulk endocytosis. Research into the comparative kinetics and mechanisms underlying these endocytosis mechanisms commonly involves time-series fluorescence microscopy of in vitro cultures. Synaptic proteins are tagged with fluorescent markers, or the synaptic vesicles are labelled with fluorescent dye. The change in fluorescence levels of individual synapses over time in response to stimuli is used to understand synaptic activity. The image analysis of these time-series images frequently requires substantial manual effort to extract the changing synaptic fluorescence intensity levels over time. This work focusses on two closely interlinked areas, the development of improved automated image analysis tools to facilitate the analysis of microscopy image data, and computational simulations to leverage the data obtained from these experiments to gain mechanistic insight into the underlying processes involved in synaptic vesicle recycling. The imaged properties of synapses within the time-series images are characterised, in terms of synapse movement during the course of an experiment. This characterisation highlights the properties which risk adding error to the extracted fluorescence intensity data, as analysis generally requires segmentation of regions of interest with fixed size and location. Where possible, protocols to optimise the manual selection of synapses in the image are suggested. The manual selection of synapses within time-series images is a common but time consuming and difficult task. It requires considerable skill on the part of the researcher to select synapses from noisy images without introducing error or bias. Automated tools for either general image segmentation or for segmentation of synapse-like puncta do exist, but have mixed results when applied to time-series experiments. This work introduces the use of knowledge of the experiment protocol into the segmentation process. The selection of synapses as they respond to known stimuli is compared against other current segmentation methods, and tools to perform this segmentation are provided. This use of synapse activity improves the quality of the segmented set of synapses over existing segmentation tools. Finally, this work builds a number of computational models, to allow published individual data points to be aggregated into a coherent view of overall synaptic vesicle recycling. The first is FM-Sim, a stochastic hybrid model of overall synapse recycling as is expected to occur during the course of an experiment. This closed system model handles the processes of exocytosis and endocytosis. It uses Bayesian inference to fit model parameters to experimental data. In particular, it uses the experimental protocol to separate the mechanisms and rates that may contribute to the observed experimental data. The second is a mathematical model of one aspect of synaptic vesicle recycling of particular interest - homoeostasis of plasma membrane integrity on the presynaptic terminal. This model provides bounds on efficiency of the studied endocytosis mechanisms at recovery of plasma membrane area during and after neuronal stimulus. Both the image analysis and the computational simulations demonstrated in this work provide useful tools and insights into current research of synaptic vesicle recycling and the role of activity-dependent bulk endocytosis. In particular, the utility of adding time-dependent experimental protocol knowledge to both the image analysis tools and the computational simulations is shown.
167

The impact of frequency modulation (FM) system use and caregiver training on young children with hearing impairment in a noisy listening environment

Nguyen, Huong Thi Thien 01 July 2011 (has links)
The two objectives of this single-subject study were to assess how an FM system use impacts parent-child interaction in a noisy listening environment, and how a parent/caregiver training affect the interaction between parent/caregiver and child. Two 5-year-old children with hearing loss and their parent/caregiver participated. Experiement 1 was conducted using an alternating design measured three communication behaviors (e.g., child's vocalization, parent/caregiver's initiation, and parent/caregiver's response) across four listening conditions (e.g., HA+Quiet, HA+Noise, FM+Quiet, and FM+Noise). Experiment 2 was conducted using a comparison within and between conditions to re-measure the communicative behaviors across the listening conditions after the parent/caregiver training. Findings of this study point to three major conclusions. First, FM system use (i.e., FM-only mode) facilitated FM01 child's ability to maintain same level of interaction in a noisy as good as in a quiet environment. Second, parent/caregiver training enhanced the impact of FM system use for one child (FM01), although parent/caregiver initiation increased for both. Third, it is important to verify the function of both FM system and HA microphones to ensure access to FM advantage.
168

Heavy metal contamination and toxicity : Studies of Macroalgae from the Tanzanian Coast

Mamboya, Florence Alex January 2007 (has links)
<p>Concentrations of various metals are elevated above background levels in several intertidal areas along the Tanzanian coasts. However, there is little available information concerning the toxicity of these metals and how the uptake of these metals by bioindicators are influenced by external factors, such as heavy rains and increased coastal eutrophication, which tend to fluctuate.</p><p>The present study focused on the uptake and toxicity of Cu and Zn in two common macroalgal species,<i> Padina gymnospora</i> (Phaeophyta) and<i> Ulva</i> <i>reticulata</i> (Chlorophyta). Laboratory studies were performed where metal content, growth (DGR), maximal quantum yields (Fv/Fm) and protein expression patterns (in <i>Ulva</i>) were measured as a response to exposure to Cu and Zn. The levels of metals accumulated in algal tissues correlated well to exposure concentrations and the longer the exposure time, the greater the uptake. However, an increased nutrient load (tested on <i>Padina</i>) or dilution of the seawater (tested on<i> Ulva</i>) affected both uptake of metals and their toxic effects. Here, DGR was more affected than Fv/Fm, suggesting DGR to be the more sensitive indicator of Cu and Zn toxicity. As shown by 2-D gel electrophoresis, more than ten proteins were up-regulated in <i>U. reticulata</i> after being exposed to Cu (1μg/L), while at higher concentrations (10 and 100 μg/L) of Cu numerous proteins were down-regulated.</p><p><i>P. gymnospora </i>was also used as a bioindicator to monitor long-term (1994–2005) and seasonal in-year variations in heavy metal concentrations in the Zanzibar Channel. No clear overall trends were revealed, but analysis of the combined dataset clearly pinpointed the most contaminated sites. It was concluded that seasonal and long-term variations, as well as environmental conditions need to be taken into consideration when using macroalgae as bioindicators.</p>
169

Heavy metal contamination and toxicity : Studies of Macroalgae from the Tanzanian Coast

Mamboya, Florence Alex January 2007 (has links)
Concentrations of various metals are elevated above background levels in several intertidal areas along the Tanzanian coasts. However, there is little available information concerning the toxicity of these metals and how the uptake of these metals by bioindicators are influenced by external factors, such as heavy rains and increased coastal eutrophication, which tend to fluctuate. The present study focused on the uptake and toxicity of Cu and Zn in two common macroalgal species, Padina gymnospora (Phaeophyta) and Ulva reticulata (Chlorophyta). Laboratory studies were performed where metal content, growth (DGR), maximal quantum yields (Fv/Fm) and protein expression patterns (in Ulva) were measured as a response to exposure to Cu and Zn. The levels of metals accumulated in algal tissues correlated well to exposure concentrations and the longer the exposure time, the greater the uptake. However, an increased nutrient load (tested on Padina) or dilution of the seawater (tested on Ulva) affected both uptake of metals and their toxic effects. Here, DGR was more affected than Fv/Fm, suggesting DGR to be the more sensitive indicator of Cu and Zn toxicity. As shown by 2-D gel electrophoresis, more than ten proteins were up-regulated in U. reticulata after being exposed to Cu (1μg/L), while at higher concentrations (10 and 100 μg/L) of Cu numerous proteins were down-regulated. P. gymnospora was also used as a bioindicator to monitor long-term (1994–2005) and seasonal in-year variations in heavy metal concentrations in the Zanzibar Channel. No clear overall trends were revealed, but analysis of the combined dataset clearly pinpointed the most contaminated sites. It was concluded that seasonal and long-term variations, as well as environmental conditions need to be taken into consideration when using macroalgae as bioindicators.
170

Heuristic Rule-Based Phase Balancing of Distribution Systems by Considering Customer Load Patterns

Ho, Cheng-Yu 10 June 2004 (has links)
In this paper, a heuristic backtracking search algorithm is proposed to adjust the phasing arrangement of primary feeders and laterals for phase balancing of distribution systems. The phase unbalance index of distribution feeders is calculated based on the phasing current magnitude of each line segment and branch, which has been solved by a 3-phase load flow program. The database of an automated mapping/facility management (AM/FM) system is used to retrieve the component attributes and topology process is executed to determine the electrical network configuration and to identify the customers served by each distribution transformer. By using the monthly energy consumption of the customers in customer information system (CIS) and the typical daily load patterns of customer classes, the hourly loading profiles of distribution transformers can be derived, which can be integrated to solve the load demand of each service zone. By this manner, the individual phase loadings of each primary feeder and lateral can be determined based on the phasing of distribution transformers and the power consumption served. The optimal phase balancing of distribution systems is performed by heuristic rule-based searching process to minimize the phase unbalance index so that the proper phasings of a primary feeder and its lateral can be assigned. To demonstrate the effectiveness of proposed methodology to enhance three-phase balancing of distribution systems, a practical distribution feeder with 2754 customers are selected for computer simulation. It is concluded that three phase balancing of distribution systems can be obtained by properly phasing design of primary feeders and laterals by considering customer load characteristics.

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