Stock assessment and behavioral studies are needed to identify habitat use and population dynamics of endangered pallid sturgeon Scahphirhynchus albus in the freelowing lower Mississippi River; however, effective sampling methods have not been evaluated. Trotlines and otter trawls were consequently fished year-round to determine the more effective gear and to determine effects of environmental variables on catch rates. Trotlines were more effective for catching large (> 600 mm FL) pallid sturgeon and neither gear was effective for catching small (100-600 mm FL) pallid sturgeon. Greater predicted probabilities of catching large pallid sturgeon with trotlines were in 9-19 °C water temperatures, 0.7-0.9 m s-1 surface current velocities, and in greater depths (up to 12 m). Results of this study provide information that can be used to maximize sampling efficiency.

The main objective of this dissertation is to develop the second generation of Distributed Digital Radio (DDR) technology. A DDR II modem provides an integrated voice/data service platform, higher data rates and better throughput performance as compared to a DDR I modem. In order to improve the physical layer performance of DDR modems an analytical framework is first developed to model the Bit Error Rate (BER) performance of Orthogonal Frequency Division Multiplexing over Frequency Modulation (OFDM/FM) systems. The use of OFDM provides a spectrally efficient method of transmitting data over LMR channels. However, the high Peak-to-Average (PAR) of OFDM signals results in either a low Signal-to-Noise Ratio (SNR) at FM receiver or a high non-linear distortion of baseband signal in the FM transmitter. This dissertation presents an analytical framework to highlight the impact of high PAR of OFDM signal on OFDM/FM systems. A novel technique for reduction of PAR of OFDM called Linear Scaling Technique (LST) is developed. The use of LST mitigates the signal distortion occurring in OFDM over FM systems. Another important factor which affects the throughput of LMR networks is the Push-to-Talk (PTT) delay. A PTT delay refers to the delay between the instant when a PTT switch on a conventional LMR radio is keyed/unkeyed and a response is observed at the radio output. It can be separated into a Receive-To-Transmit Switch Interval (RTSI) or a Transmit-To-Receive Switch Interval (TRSI). This dissertation presents the typical RTSI delay values, distributions and their impact on throughput performance of LMR networks. An analytical model is developed to highlight the asymmetric throughput problem and the unintentional denial of service (UDOS) occurring in heterogeneous LMR networks consisting of radios with different PTT delay profiles. This information will be useful in performance and capacity planning of LMR networks in future.

University, Diss., 2002--Bonn.

No description available.

The main topic of this diploma thesis is ARE (resistance) proteins from the ABC-F family of the second class of ABC proteins. ARE proteins confer resistance to antibiotics that bind to a large ribosomal subunit and therefore inhibit proteosynthesis. One of the ARE proteins is the Lmr (C) protein, which is part of the linkomycin biosynthesis cluster of Streptomyces lincolnensis, and according to new results, Lmr (C) does not have to be just resistant protein but may have also regulatory function. We decided to study Sco0636, the closest homologue to Lmr (C) in Streptomyces coelicolor, which is a model organism in the study of secondary metabolism. Thanks to the production of color pigments, it is possible to monitor the effect of ARE proteins on secondary metabolism directly on the plates. I prepared the deletion mutant and the strain with constitutive expression of sco0636, and observed the effect on the phenotype. I followed the production of a blue asset and set a minimum inhibitory concentration to selected antibiotics, which bind to the ribosome. I have found that Sco0636 gives high resistance to tiamulin and so it has been named TiaA. The deletion of gene sco0636 accelerated production of actinorodine, and constitutive expression of this gene slowed down production. Keywords: ABC proteins,...

The main topic of this diploma thesis is ARE (resistance) proteins from the ABC-F family of the second class of ABC proteins. ARE proteins confer resistance to antibiotics that bind to a large ribosomal subunit and therefore inhibit proteosynthesis. One of the ARE proteins is the Lmr (C) protein, which is part of the linkomycin biosynthesis cluster of Streptomyces lincolnensis, and according to new results, Lmr (C) does not have to be just resistant protein but may have also regulatory function. We decided to study Sco0636, the closest homologue to Lmr (C) in Streptomyces coelicolor, which is a model organism in the study of secondary metabolism. Thanks to the production of color pigments, it is possible to monitor the effect of ARE proteins on secondary metabolism directly on the plates. I prepared the deletion mutant and the strain with constitutive expression of sco0636, and observed the effect on the phenotype. I followed the production of a blue asset and set a minimum inhibitory concentration to selected antibiotics, which bind to the ribosome. I have found that Sco0636 gives high resistance to tiamulin and so it has been named TiaA. The deletion of gene sco0636 accelerated production of actinorodine, and constitutive expression of this gene slowed down production. Keywords: ABC proteins,...

The concept of using spread spectrum and open radio standards to provide license-free, short range Peer-to-Peer (P2P) communication is explored. This research makes use of the Time Compression Overlap Add (TC-OLA) algorithm to transparently spread the spectrum of the Digital Mobile Radio (DMR) standard; this allows for reuse of existing hardware, software, and expertise relating to this well established protocol. Initial high level hardware designs of a communication device established the need to implement a proof of concept system which could be validated against Radio Frequency (RF) regulations. This proof of concept system was constructed using a hardware implementation of DMR processed through custom TC-OLA blocks in GNU Radio (GR). A spectral and performance analysis of this system was performed, showing that this approach has several benefits over existing license free communication options. / Graduate / 2020-07-11

We are interested in measuring the in situ antenna performance in analog land mobile radio (LMR) FM systems. The gain (efficiency and directivity) and self-impedance of an antenna sufficiently characterize its performance and a number of traditional methods exist to measure these quantities. However it is hard to do antenna gain measurements using these methods. Furthermore, it turns out that volumetric antenna gain measurements are not quite relevant for understanding in situ performance. In this thesis, we present a novel approach for directly measuring the in situ performance of antennas in analog LMR systems. The procedure involves receiving an FM signal simultaneously using the antenna under test (AUT) and a reference antenna. Both received signals are demodulated to audio using separate but identical receivers. Then a convenient method for characterizing the audio signal quality is to analyze the private line (PL) tone. The PL tone signal-to-noise ratio (SNR) is calculated by measuring the power of the tone relative to the sub-audio noise power. The PL tone SNR for both antenna systems is compared as it provides a ``bottom line'' evaluation of the antenna performance. The audio SNR can also be mapped to RF SNR using a theoretical method. From simulation and experimental studies, we conclude that the RF SNR estimated using this technique is within 0.5 dB of the actual value for RF SNR values between +3 and +36 dB. Finally, we demonstrate this procedure in actual in situ LMR antenna measurements. / Master of Science

The genus Streptomyces produces more than a half of the known bioactive substances, ranking it among the most important bacterial taxons. Streptomyces lincolnensis ATCC 25466 encodes a biosynthetic gene cluster for lincomycin biosynthesis in its genome. Apart from the biosynthetic and regulatory genes, the cluster also contains three resistance genes, lmr(A), lmr(B) a lmr(C), which could protect of the host from the toxicity of a synthesized antibiotic. The Lmr(C) protein belongs to ARE proteins which generaly confer resistance to clinically important classes of antibiotics: macrolides, streptogramins, lincosamides and pleuromutilins. In addition to antibiotic producers, ARE proteins are also present in pathogenic microorganisms. However, the resistance mechanism conferred by these protins which belong to ABC transporters, even though they lack the transmembrane domain, have not been characterized yet. This makes the ARE proteins an interesting subject of the research. Using deletion mutants in resistance genes lmr(A), lmr(B) a lmr(C) we studied their effect on the lincomycin production and resistance to lincosamides, lincomycin and clindamycin with special focus on the function of the lmr(C). We have found that deletion of lmr(C) does not significantly influence lincomycin production and...

Um total de 168 machos Bos indicus foram abatidos depois de 8, 15, 35, 49, 63, 91, 120 e 154 dias após a aplicação de eprinomectina e ivermectina (convencional e longa ação), e 18 diferentes tecidos comestíveis foram avaliados quanto à concentração de resíduos dessas moléculas para verificar se o período de carência estabelecido garante o esgotamento em todos eles, em níveis abaixo dos limites máximos estabelecidos por agências reguladoras internacionais, com o objetivo de abordar questões relacionadas à barreiras técnico-comerciais entre países. Além disso, visou analisar se a concentração desses resíduos é afetada pelo processamento térmico, para avaliar a coerência de se considerar para produtos enlatados, os mesmos limites determinados para produtos crus. As análises de concentração de resíduos foram feitas por HPLC (sistema LC-MS/MS). Os dados foram transformados para escala \"logaritmo natural\" e foi realizada análise de variância, teste de comparação múltipla, análises de regressão e de correlação. Os resultados demonstraram que os níveis de eprinomectina encontrados foram abaixo de todos os limites máximos de resíduos (LMR), ao longo de todos os períodos e tecidos avaliados. Com relação à ivermectina, padrões diferenciados de distribuição foram observados, porém ao final do período de carência, dos 18 tecidos avaliados, 17 apresentaram concentrações dentro dos LMR, com exceção do sítio de aplicação, em que se observou alto nível de dispersão e valores acima de alguns LMR, mesmo após cumprido o período de carência indicado na bula. Foram observadas correlações significativas (P<0,01) entre concentrações residuais em fígado e em tecidos musculares, sendo que as equações obtidas podem ser úteis em programas de vigilância. O processamento térmico afetou os resultados de concentração de resíduos de ivermectina em alguns músculos testados, que apresentaram concentração significativamente mais elevada (P<0,05) após a esterilização. Conclui-se que a eprinomectina é mais recomendada que a ivermectina, no que tange ao propósito de se evitar violações de LMR; que foram distintos os padrões de distribuição de resíduos em cada tecido avaliado, mas que se respeitado o período de carência, praticamente todos os tecidos estarão abaixo dos LMR estabelecidos internacionalmente, exceto pelo sítio de aplicação; portanto, que o tempo de depleção de resíduos do sítio de aplicação (até abaixo dos LMR) deveria ser considerado para a determinação do período de carência dos medicamentos; e que é fundamental haver uma harmonização dos LMR em esfera global. Além disso, observou-se que o processamento térmico a que os enlatados são submetidos provoca níveis discrepantes (mais elevados) de resíduos em relação aos produtos crus e isso deve ser levado em consideração nas análises de vigilância, pois pode gerar incertezas quanto à possibilidade de violação em mercados importadores. / A total of 168 Bos indicus males were slaughtered after 8, 15, 35, 49, 63, 91, 120 and 154 days post-application of eprinomectin and ivermectin (conventional and long-acting), and 18 different edible tissues were evaluated for the residue concentration of these molecules to verify if the established withdrawal period guarantees depletion in all of them, at levels below the maximum limits established by regulatory agencies around the world, in order to address issues related to technical trade barriers between countries. In addition, it aimed to analyze if the concentration of these residues is affected by thermal processing, to evaluate the consistency of considering for canned goods, the same limits determined for raw products. Residue concentration analyzes were performed using HPLC (LC-MS / MS system). Data were converted into \"natural logarithm\" scale and analysis of variance, multiple comparison test, regression and correlation analysis were performed. Results showed that eprinomectin levels were found to be below all maximum residue limits (MRL) throughout all periods and tissues evaluated. Regarding ivermectin, differentiated distribution patterns were observed, but at the end of the withdraw period, 17 of the 18 tissues evaluated had concentrations within the MRLs, except for the injection site, where a high level of dispersion was observed and values above some of MRLs recommended by the main international regulations, even after having been completed the withdraw period indicated in the instructions. Significant correlations (P <0.01) were observed between residual concentrations in liver and muscle tissues, and the equations obtained may be useful in surveillance programs. The thermal processing affected ivermectin concentration results in some tested muscle types, which had a significantly higher residue concentration (P <0.05) after sterilization. It was concluded that eprinomectin is more recommended than ivermectin for the purpose of avoiding MRL violations; that the residue distribution patterns in each tissue were different, but if the withdrawal period is met, almost all tissues will be below internationally established MRLs except for the application site; therefore, that the depletion time of injection site residues (to below the MRL) should be considered for the determination of the drug withdrawal period; and that harmonization of MRLs is essential in the global sphere. In addition, it has been observed that the thermal processing to which the canned products are subjected causes discrepant (higher) levels of residues in relation to the raw products and this must be taken into account in surveillance analyzes, since it may generate uncertainties as to the possibility of violation in importers markets.