441 |
Fit condition and fit-up behavior - Impact on design and construction of steel I-girder bridgesNguyen, Thanh Van 07 January 2016 (has links)
This research provides quantitative data to aid engineers in the selection of various attributes to facilitate fit-up during I-girder bridge construction. Concepts and procedures for explicit calculation of locked-in forces due to cross-frame detailing are developed and discussed. Fit-up forces are evaluated and discussed for a suite of bridge cases analyzed in this research. Bridge cases with difficult fit-up are highlighted. Recommendations for erection procedures are provided to facilitate fit-up. The research investigates and recommends beneficial staggered cross-frame framing arrangements that are applicable to straight skewed bridges, framing arrangements with liberal offsets around bearing lines at interior pier in continuous spans bridges, and the use of staggered versus lean-on cross-frame arrangements in straight skewed bridges. The research also addresses the impacts of cross-frame detailing methods, that is, the “fit condition” of the structure, on cross-frame forces, girder elevations, girder layovers, girder stresses, and vertical reactions in the completed bridges.
|
442 |
Investigation and characterisation of the genetic variation in the coding region of the glycine N-acyltransferase gene / Rencia van der SluisVan der Sluis, Rencia January 2015 (has links)
Thorough investigation of the glycine conjugation pathway has been neglected over the last 30 years. Environmental factors, nutrition, and the chronic use of medications are increasing the exposure of humans to benzoate and drugs that are metabolized to acyl-CoA intermediates. Glycine conjugation of mitochondrial acyl-CoAs, catalysed by glycine N-acyltransferase (GLYAT, E.C. 2.3.1.13), is an important metabolic pathway responsible for maintaining adequate levels of free coenzyme A (CoASH). However, because of the small number of pharmaceutical drugs that are conjugated to glycine, the pathway has not yet been characterised in detail. Therefore, one of the objectives of this thesis was to develop a better understanding of glycine conjugation and its role in metabolism. In humans and animals a number of endogenous and xenobiotic organic acids are conjugated to glycine. Glycine conjugation has generally been assumed to be a detoxification mechanism, increasing the water solubility of organic acids in order to facilitate urinary excretion. However, recently it was proposed that the role of the amino acid conjugations, including glycine conjugation, is to regulate systemic levels of amino acids that are also utilised as neurotransmitters in the central nervous systems of animals. The glycine deportation hypothesis was based on the observation that, compared to glucuronidation, glycine conjugation does not significantly increase the water solubility of aromatic acids. A thorough review of the literature for this thesis showed that the major role of glycine conjugation, however, is to dispose of the end products of phenylpropionate metabolism. The review also introduced the new perspective that mitochondrial glycine conjugation prevents the accumulation of benzoate in the mitochondrial matrix by forming hippuric acid a less lipophilic conjugate that can be more readily transported out of the mitochondria. Although organic anion transporters can export benzoate from the matrix, this process would likely be futile because benzoic acid can simply diffuse back into the matrix. Hippurate, however, is significantly less lipophilic and therefore less capable of diffusing into the matrix. It is therefore not the transport out of the mitochondrial matrix that is facilitated by glycine conjugation, but rather the ability of the glycine conjugates to re-enter the matrix that is decreased. Lastly, glycine conjugation of benzoate also exacerbates the dietary deficiency of glycine in humans. Because the resulting shortage of glycine can negatively influence brain neurochemistry and the synthesis of collagen, nucleic acids, porphyrins, and other important metabolites, the risks of using benzoate as a preservative should not be underestimated.
To date, no defect of the glycine conjugation pathway has been reported and this, together with the fact that GLYAT plays an important role in hepatic metabolism, suggests that this pathway is essential for survival. GLYAT activity affects mitochondrial ATP production, glycine availability, CoASH availability and the toxicity of various organic acids. Therefore, variation in the glycine conjugation pathway could influence liver cancer, musculoskeletal development and mitochondrial energy metabolism. Significant interindividual variation exists in glycine conjugation capacity. The molecular basis for this variability is not known. The main aim of this thesis was to investigate and characterise the genetic variation in the coding region of the GLYAT gene. This was accomplished by firstly, investigating the influence of non-synonymous single nucleotide polymorphisms (SNPs) on the enzyme activity of a recombinant human GLYAT and secondly, by analysing the level of genetic
variation in the coding region of the GLYAT gene using existing worldwide population data. To investigate the influence of non-synonymous SNPs in the GLYAT gene on the enzyme activity, a recombinant human GLYAT was prepared, and characterised. Site-directed mutagenesis was used to generate six variants of the enzyme (K16N; S17T; R131H; N156S; F168L; R199C). The variants were expressed, purified, and enzymatically characterised. The enzyme activities of the K16N, S17T and R131H variants were similar to that of the wild-type, whereas the N156S variant was more active, the F168L variant less active, and the R199C variant was inactive. The results showed that SNP variations in the human GLYAT gene can influence the kinetic properties of the enzyme. The genetic variation data of the human GLYAT open reading frame (ORF) available on public databases was investigated by formulating the hypothesis that due to the essential nature of the glycine conjugation pathway, the genetic variation in the ORF of the GLYAT gene should be low and that deleterious alleles will be found at low frequencies. Data from the i) 1000 Genome Project, ii) the HapMap Project, and iii) the Khoi-San/Bantu Sequencing Project was downloaded from available databases. Sequence data of the coding region of a small cohort of South African Afrikaner Caucasian individuals was also generated and included in the analyses. In the GLYAT ORF of the 1537 individuals analysed, only two haplotypes (S156 and T17S156) out of 14 haplotypes were identified in all populations as having the highest haplotype frequencies (70% and 20% respectively). The S156C199 and S156H131 haplotypes, which have a deleterious effect on the enzyme activity of a recombinant human GLYAT, were detected at very low frequencies. The results of this study indicated that the GLYAT ORF is remarkably conserved, which supports the hypothesis that the glycine conjugation pathway is an essential detoxification pathway. The findings presented in this thesis highlight the importance that future investigations should determine the in vivo capacity of the glycine conjugation pathway for the detoxification of benzoate and other xenobiotics. / PhD (Biochemistry), North-West University, Potchefstroom Campus, 2015
|
443 |
Investigation and characterisation of the genetic variation in the coding region of the glycine N-acyltransferase gene / Rencia van der SluisVan der Sluis, Rencia January 2015 (has links)
Thorough investigation of the glycine conjugation pathway has been neglected over the last 30 years. Environmental factors, nutrition, and the chronic use of medications are increasing the exposure of humans to benzoate and drugs that are metabolized to acyl-CoA intermediates. Glycine conjugation of mitochondrial acyl-CoAs, catalysed by glycine N-acyltransferase (GLYAT, E.C. 2.3.1.13), is an important metabolic pathway responsible for maintaining adequate levels of free coenzyme A (CoASH). However, because of the small number of pharmaceutical drugs that are conjugated to glycine, the pathway has not yet been characterised in detail. Therefore, one of the objectives of this thesis was to develop a better understanding of glycine conjugation and its role in metabolism. In humans and animals a number of endogenous and xenobiotic organic acids are conjugated to glycine. Glycine conjugation has generally been assumed to be a detoxification mechanism, increasing the water solubility of organic acids in order to facilitate urinary excretion. However, recently it was proposed that the role of the amino acid conjugations, including glycine conjugation, is to regulate systemic levels of amino acids that are also utilised as neurotransmitters in the central nervous systems of animals. The glycine deportation hypothesis was based on the observation that, compared to glucuronidation, glycine conjugation does not significantly increase the water solubility of aromatic acids. A thorough review of the literature for this thesis showed that the major role of glycine conjugation, however, is to dispose of the end products of phenylpropionate metabolism. The review also introduced the new perspective that mitochondrial glycine conjugation prevents the accumulation of benzoate in the mitochondrial matrix by forming hippuric acid a less lipophilic conjugate that can be more readily transported out of the mitochondria. Although organic anion transporters can export benzoate from the matrix, this process would likely be futile because benzoic acid can simply diffuse back into the matrix. Hippurate, however, is significantly less lipophilic and therefore less capable of diffusing into the matrix. It is therefore not the transport out of the mitochondrial matrix that is facilitated by glycine conjugation, but rather the ability of the glycine conjugates to re-enter the matrix that is decreased. Lastly, glycine conjugation of benzoate also exacerbates the dietary deficiency of glycine in humans. Because the resulting shortage of glycine can negatively influence brain neurochemistry and the synthesis of collagen, nucleic acids, porphyrins, and other important metabolites, the risks of using benzoate as a preservative should not be underestimated.
To date, no defect of the glycine conjugation pathway has been reported and this, together with the fact that GLYAT plays an important role in hepatic metabolism, suggests that this pathway is essential for survival. GLYAT activity affects mitochondrial ATP production, glycine availability, CoASH availability and the toxicity of various organic acids. Therefore, variation in the glycine conjugation pathway could influence liver cancer, musculoskeletal development and mitochondrial energy metabolism. Significant interindividual variation exists in glycine conjugation capacity. The molecular basis for this variability is not known. The main aim of this thesis was to investigate and characterise the genetic variation in the coding region of the GLYAT gene. This was accomplished by firstly, investigating the influence of non-synonymous single nucleotide polymorphisms (SNPs) on the enzyme activity of a recombinant human GLYAT and secondly, by analysing the level of genetic
variation in the coding region of the GLYAT gene using existing worldwide population data. To investigate the influence of non-synonymous SNPs in the GLYAT gene on the enzyme activity, a recombinant human GLYAT was prepared, and characterised. Site-directed mutagenesis was used to generate six variants of the enzyme (K16N; S17T; R131H; N156S; F168L; R199C). The variants were expressed, purified, and enzymatically characterised. The enzyme activities of the K16N, S17T and R131H variants were similar to that of the wild-type, whereas the N156S variant was more active, the F168L variant less active, and the R199C variant was inactive. The results showed that SNP variations in the human GLYAT gene can influence the kinetic properties of the enzyme. The genetic variation data of the human GLYAT open reading frame (ORF) available on public databases was investigated by formulating the hypothesis that due to the essential nature of the glycine conjugation pathway, the genetic variation in the ORF of the GLYAT gene should be low and that deleterious alleles will be found at low frequencies. Data from the i) 1000 Genome Project, ii) the HapMap Project, and iii) the Khoi-San/Bantu Sequencing Project was downloaded from available databases. Sequence data of the coding region of a small cohort of South African Afrikaner Caucasian individuals was also generated and included in the analyses. In the GLYAT ORF of the 1537 individuals analysed, only two haplotypes (S156 and T17S156) out of 14 haplotypes were identified in all populations as having the highest haplotype frequencies (70% and 20% respectively). The S156C199 and S156H131 haplotypes, which have a deleterious effect on the enzyme activity of a recombinant human GLYAT, were detected at very low frequencies. The results of this study indicated that the GLYAT ORF is remarkably conserved, which supports the hypothesis that the glycine conjugation pathway is an essential detoxification pathway. The findings presented in this thesis highlight the importance that future investigations should determine the in vivo capacity of the glycine conjugation pathway for the detoxification of benzoate and other xenobiotics. / PhD (Biochemistry), North-West University, Potchefstroom Campus, 2015
|
444 |
Project work, independence and critical thinkingEklöf, Anders January 2014 (has links)
This thesis studies how students do projects in a Swedish upper secondaryschool. The students have to produce products and at the same time provethem self as independent in relation to the teachers, and negotiate therequirements of the project setting and the written instructions within thegroup. The study focuses on what comes out as problematic for the students,how they solve these dilemma situations and what resources are used in orderto do so.A choice was made only to analyse student group interaction in parts ofthe project process where the teachers were not physically present thus fillinga research gap.The empirical material was collected during three years in sex secondaryschool classes through filmed sessions of groups or pairs working with theirproject.Each of the four articles primarily focuses a special dilemma; structure,independence, instructions and critical thinking. By combining Goffman’sframe analysis with the concepts of risk and uncertainty from a Risk – societyperspective, issues related to what it means to do project work asindependent, critical 21st-century learner are illustrated and discussed.The choice to look only at situations in which students have to managewithout the aid of a physically present teacher illuminates several practicalconsequences like an unwillingness to go to the teacher and ask questions andan increased concentration on and interpretation of the written instructions. Adevelopment of Miller and Parlett’s (1974) discussion of student approach tocues are suggested. The concept of the cue choosing student are constructedin order to better respond to demands from an individualised interactionsociety. The study also emphasises how the students have to balance differentframeworks in order to be both authors and assessed students. Byimplementing a risk society perspective new ways of analysing andunderstanding independence and classroom interaction is suggested and arecontextualization of critical thinking proposed.
|
445 |
AN IMPROVED AMI CODE USED IN TELEMETRY SYSTEMDongkai, Yang, Qishan, Zhan, Lung, Cheng Lee 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / An Improved AMI (Alternate Mark Inverse) Code used in telemetry system is proposed, its implementation and properties analysis are reported, including error performance analysis, power spectrum analysis, the relationship between acqusition probability of the first frame marker and error threshold and length of frame marker, etc. This type of code has the approximately identical power spectrum performance as the AMI Code. In addition, there have no long continuous zeroes in the data stream, which will cause phase-locked loop to fail. Using the Improved AMI Code, the equal probability of 0 and 1 is changed, which will increase acqusition probability of the first frame marker. Detailed description about how to create the Improved AMI Code is also discussed in this paper.
|
446 |
The strategic framing of foreign policy : A comparative case study between the United State’s invasion of Iraq and the Russian annexation of CrimeaMännistö, Ida January 2016 (has links)
This research presents a comparative case study between the Russian annexation of Crimea in 2014 and the United State’s invasion of Iraq in 2003. It specifically examines how the two interventions were framed by the political executives. Frame theory and a qualitative content analysis served as theoretical and methodological benchmarks to assess selected speeches and public statements delivered by president George W. Bush and Vladimir Putin, in order to detect similar motives and justification patterns for the armed occupations. Four distinct war frames emerged from the text material: prevention, common good, state liability and imposed war. The results demonstrate that state leaders are prone to strategically communicate their military ambitions and legitimize their policy agendas through corresponding framing processes.
|
447 |
A socio-pragmatic and structural analysis of code-switching among the Legoli speech community of Kangeni, Nairobi, KenyaGimode, Jescah Khadi January 2015 (has links)
The study is an in-depth examination of code-switching in the Logoli speech community in the cosmopolitan Kangemi informal settlement area on the outskirts of the city of Nairobi. The aim of the study is to investigate the sociolinguistic and structural developments that result from urban language contact settings such as Kangemi. The main objective is to identify and illustrate the social motivations that influence the tendency of the Logoli speakers to alternate codes between Lulogoli, Kiswahili and English in the course of their routine conversations as well as the structural patterns that emerge in the process of code-switching. Various methodological techniques were used in the gathering of data, including questionnaire surveys, oral interviews, tape recordings and ethnographic participant-observation techniques are highlighted. Extracts from the corpus were analysed within a theoretical framework based on two models, namely the Markedness Model and the Matrix Language Frame Model, both developed by Myers-Scotton. The study identified and interpreted, within the Markedness Model framework, the key social variables that determine code-switching behaviour among the Logoli speech community. These include age, education, status and the various social domains of interaction. In the light of these factors, the researcher was able to explain the tendency to switch codes in different settings and confirm the study’s assumption that urban-based social factors largely determine the motivations for and the patterns of code-switching. This lead to the conclusion that code-switching is not a random phenomenon but a strategy and a negotiation process that aims at maximizing benefits from interaction. Structural features of the corpus were also identified and analysed within the Matrix Language Frame Model. The assumptions of the model were tested and found to be supported by numerous examples from the data. A number of recommendations were made for further research on minority languages in Kenya and the need for language policy in Kenya to be formulated to take these language groups into consideration. / Linguistics and Modern Languages
|
448 |
Precious Bits: Frame Synchronization in Jet Propulsion Laboratory's Advanced Multi-Mission Operations System (AMMOS)Wilson, Elizabeth (Betsy) 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Jet Propulsion Laboratory’s (JPL) Advanced Multi-Mission Operations System (AMMOS) system processes data received from deep-space spacecraft, where error rates are high, bit rates are low, and every bit is precious. Frame synchronization and data extraction as performed by AMMOS enhance data acquisition and reliability for maximum data return and validity. Unique aspects of data phase determination, sync acquisition and sync loss and other bit-level topics are covered.
|
449 |
NEW TELEMETRY HARDWARE FOR THE DEEP SPACE NETWORK TELEMETRY PROCESSOR SYSTEMPuri, Amit, Ozkan, Siragan, Schaefer, Peter, Anderson, Bob, Williams, Mike 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper describes the new Telemetry Processor Hardware (TPH) that Avtec Systems has developed for the Deep Space Network (DSN) Telemetry Processor (TLP) system. Avtec is providing the Telemetry Processor Hardware to RTLogic! for integration into the Telemetry Processor system. The Deep Space Network (DSN) is an international network of antennas that supports interplanetary spacecraft missions for exploration of the solar system and the universe. The Jet Propulsion Laboratory manages the DSN for NASA. The TLP system provides the capability to acquire, process, decode and distribute deep space probe and Earth orbiter telemetry data. The new TLP systems will be deployed at each of the three deep-space communications facilities placed approximately 120 degrees apart around the world: at Goldstone, California; near Madrid, Spain; and near Canberra, Australia. The Telemetry Processor Hardware (TPH) supports both CCSDS and TDM telemetry data formats. The TPH performs the following processing steps: soft-symbol input selection and measurement; convolutional decoding; routing to external decoders; time tagging; frame synchronization; derandomization; and Reed-Solomon decoding. The TPH consists of a VME Viterbi Decoder/MCD III Interface board (VM-7001) and a PCI-mezzanine Frame Synchronizer/Reed-Solomon Decoder (PMC- 6130-J) board. The new Telemetry Processor Hardware is implemented using the latest Field Programmable Gate Array (FPGA) technology to provide the density and speed to meet the current requirements as well as the flexibility to accommodate processing enhancements in the future.
|
450 |
HARDWARE DOWNLOADABLE MULTI-FUNCTION TELEMETRY INPUT MODULENicolais, Ray, Nicolo, Stephen J., Snyder, Ed 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper describes a Multi-Function Telemetry Input Module (TIM). The TIM module includes a 30 Mbps PCM frame synchronizer, a time code translator/generator, a PCM simulator and a tunable bit synchronizer all on a single PCI card. The module uses a generic architecture including: high density Field Programmable Gate Arrays (FPGAs), look-up table memory, dual port A/B data buffer memory and a full function PCI interface. The FPGA and the logic function of the card are downloadable via the PCI interface. This allows a single module to support many hardware functions in a telemetry front-end. The TIM is an integral part of a PC-based Advanced Telemetry Processing and Display System. This concept for hardware design ushers in a new generation of flexible downloadable telemetry products.
|
Page generated in 0.048 seconds