Background: Sports have a significant impact on people all around the world. Although sport brings a lot of joy, a sense of togetherness, and pride, it also involves ethically difficult issues such as doping. Doping in sports is a growing global concern that jeopardizes sports ethics, values, and integrity (The World Anti-Doping Agency WADA, a). Previous research has mainly approached the topic by understanding athletes’ motivation behind the decision to dope. Hence, there is a growing need to understand athletes’ attitudes and beliefs towards clean sports. Aim: This study aimed to comprehensively understand athletes’ attitudes and beliefs on reaching the top without doping and their beliefs on whether doping affects the results of competitions at the national and international levels. Also, it was examined whether variables such as age, gender, testing history, and sports have any distinguished matter on athletes’ attitudes towards clean sports. Method: A cross-sectional mixed-methods study explored athletes' attitudes and beliefs on clean sports. A total of 73 tested athletes (response rate 14,4%) completed a web-based "Assessments of Doping Control and FINCIS Activities" -survey. Results: In this research, athletes’ age, gender, testing history, and sports did not show any significance concerning athletes' attitudes towards reaching the national and international tops without doping. In the open-ended questions, athletes expressed trust in national-level competitions but had more suspicions about international competitions. Conclusion: The results suggest that the athletes in this research reported positive attitudes and beliefs in competing clean. However, it is challenging to determine whether athletes feel that they need to answer “correctly” and according to the values of clean sports. Therefore, it is important to continue studying athletes’ attitudes and clean sports.

<p>Sensorineural hearing loss imparts two serious hearing deficits in hearing-impaired people: reduced dynamic range of hearing and reduced frequency selectivity. Psychophysically, these deficits render loss of speech audibility and speech intelligibility to a hearing-impaired person. Studies of an impaired cochlea in cats have shown that the hearing loss originates from damage to or complete loss of inner and outer hair cells. Neurophysiology of an impaired cochlea in cats shows that the tuning curves of the auditory nerve fibers become elevated and broadened. Amplification in hearing aids has been used to restore audibility in hearing-impaired people. Multiband compression has been commercially available in conventional hearing aids to compensate for the reduced dynamic range of hearing. However, little has been achieved to improve the intelligibility of speech in the hearing-impaired people. The aim of this thesis is to restore not only the speech audibility in a hearing-impaired person, but also to improve their speech intelligibility through some hearing-aid signal processing. The compensation technique used in this thesis for speech intelligibility is based on the hypothesis that a narrowband response of the auditory nerve fibers to speech signals ensure phonemic discriminability in the central nervous system.</p><p>Miller et al. [1999] have proposed contrast-enhancing frequency shaping ( CEFS) to compensate for the broadband responses of the fibers to first and second formants (Fl and F2) of a speech stimulus. Bruce [2004] has shown that the multiband compression can be combined with CEFS without counteracting each other. In Bruce's algorithm, a multiband compressor is serially combined with a time-domain CEFS filter. The MICEFS algorithm, herein presented, is a combination of multiband compression and an improved version of CEFS implemented in the frequency domain. The frequency domain implementation of MICEFS has improved the time delay response of the algorithm by 10 ms as compared to series implementation proposed by Bruce. The total time delay of the MICEFS algorithm is 16 ms, which is still longer than the standard time delay of 10 ms in hearing aids. The MICEFS algorithm was tested on a computational model of auditory periphery [Bruce et al., 2003] using a synthetic vowel and a synthetic sentence. The testing paradigm consisted of five conditions: 1) unmodified speech presented to a normal cochlea; 2) speech modified with halfgain rule presented to an impaired cochlea; 3) CEFS modified speech presented to the impaired cochlea; 4) speech modified with MICEFS presented to the impaired cochlea, and; 5) MICEFS-modified speech with some added noise in the formant estimation presented to an impaired cochlea. The spectral enhancement filter used in MICEFS has improved the synchrony capture of the fibers to the first three formants of a speech stimulus. MICEFS has also restored the correct tonotopic representation in the average discharge rate of the fibers at the first three formants of the speech.</p> / Thesis / Master of Applied Science (MASc)

<p dir="ltr">Each year, approximately 1.35 million people die globally due to vehicle crashes, and in the United States alone, 42,915 traffic fatalities were recorded in 2021, reflecting a 10.5% increase from 2020 and an 18% increase from 2019. Driver fatigue and drowsiness significantly contribute to these fatalities, as fatigue severely impairs a driver’s alertness and responsiveness, leading to a higher risk of accident. Given the prevalence of drowsy driving accidents, it is crucial to implement advanced systems that alert drivers to their drowsy condition, significantly reducing traffic-related deaths and injuries. While these systems have shown significant effects in reducing the risks related to drowsy driving, most commercially available and widely researched alert systems heavily rely on auditory and visual sensory channels. These modalities may cause "alarm fatigue," leading drivers to ignore or deactivate the systems entirely, and result in a lower driving experience. Due to their frequent occurrence and potential annoyance, the National Highway Traffic Safety Administration (NHTSA) recommends that auditory warnings, which are the most commonly used modality in current driver alert systems, are generally unsuitable for first-stage cautionary alerts. Despite NHTSA human factors guidance, most in-vehicle warning systems consist of auditory and visual modalities, even in the first cautionary stage alerts. Therefore, advanced alerting systems that balance the functionality of alerts and driving experience, using non-audio and non-visual modalities, are needed.</p><p dir="ltr">With this motivation, the purpose of this Ph.D. dissertation work is to propose a novel approach to both olfactory and climate adaptive alerting systems and demonstrate their usability in in-vehicle engagement experiences. In Study 1 (Chapter 3), the use of behavioral metrics and physiological sensing was validated to assess drivers' cognitive states during driving. This validation laid the groundwork for the future evaluation of the effects of the proposed alerting system in Study 2(Chapter 4) and Study 3 (Chapter 5). In Study 2, the impact of olfactory and climate stimuli on drivers' cognitive states was investigated by studying time-variant changes. This investigation helped determine if the proposed stimuli can be effectively utilized in driver alerting systems. In Study 3, the proposed sensory-integrated alerting adaptive systems were developed and evaluated for their effect on drivers in a drowsy state. The evaluations focused on the systems’ abilities to provide a sufficient salient effect, sustained arousal effect, and driver satisfaction.</p><p dir="ltr">This dissertation introduces a new approach to driving alert systems to ensure both alert functionality and driving experience. Ultimately, this work offers a new direction for developing advanced alerting systems, particularly for first-stage warnings.</p>

Master of Landscape Architecture / Department of Landscape Architecture/Regional and Community Planning / Stephanie A. Rolley / Economically insecure times require reduction of energy and land consumption, enhancement of socio-economic and environmental quality of life, and reutilization of neglected existing structures and sites. Traditional planning and design dictates through top-down policy and ordered master planning. In contrast, interactive smart technology simulating human cognitive reactions offers an alternative design framework - an intelligent, adaptive environment – capable of redefining contemporary public open space design. Traversing through the neglected Fifth Ward north of downtown St. Louis, the adaptive reutilization of the abandoned Iron Horse Trestle interurban elevated railroad and subway applies the Sense Respond Adapt Mutate Emerge conceptual framework (the S.R.A.M.E. Strategy) by utilizing existing resources to create an interconnected, emergent open space network. Ten unique sites along the Iron Horse Trestle are initially embedded with sensory devices capable of gathering and synthesizing learned information. The real-time actions translate into physical structural responses. The site specifi c reactions extend outwards as structural adaptations to indeterminate changes from trail users. The evolving structural form connects and mutates the existing structure. Similar to a Choose your own adventure gamebook, the Trestle’s open-ended and reactive programmatic strategies emerge as a series of potential options for future inclusionary, interactive designs. By selectively enhancing, creating, or enabling an open space system reacting to real-time actual user needs over time directly along the Trestle line, the S.R.A.M.E. Strategy offers a potential alternative framework for the indirect revitalization of neglected infrastructural and economic conditions, a residential rejuvenation catalyst, and future socio-economic and ecological sustainable living patterns education tool. The Trestle’s revitalization serves as an education tool critiquing contemporary landscape architecture and general design practice - the static, dictated, and consumptive. Intelligent adaptive environments offer an alternative framework enabling interactive design decision making capabilities to the users as options evolving over time.

O Brasil é o segundo país no mundo em número de academias de ginástica, contando atualmente com cerca de 30 mil unidades. Apesar da transição no modelo de gestão e filosofia das academias do fitness para o wellness, muitas ainda propagam em seus ambientes o culto ao corpo magro e atlético, dietas sem fundamentação nutricional e consumo descontrolado de suplementos. Crescem as evidências de que uma parcela significativa dos frequentadores de academias desenvolve um comprometimento exacerbado à prática de exercícios físicos, gerando até uma dependência patológica. O objetivo foi determinar a associação entre dependência de exercício físico (DEF), consumo de suplementos e insatisfação da imagem corporal em frequentadores de academias. Para tanto foi empregada a Escala de Comprometimento com Exercício Físico (CEF) em uma amostra de 227 frequentadores, maiores de 19 anos, de ambos os sexo em três academias. Foi realizada entrevista individual com emprego de anamnese nutricional para determinar o perfil de consumo suplementar, avaliação antropométrica, da imagem corporal, do compromisso ao exercício físico assim como de participação na academia. A frequência de DEF nas academias foi de 66% e sendo que as chances estimadas deste ser consumidor de suplementos de 4,53. Os indivíduos dependentes de exercício físico são jovens, com maior chance de pertencer ao sexo masculino, frequentar a academia > 5 vezes por semana, consumir mais de um tipo de suplemento e praticar musculação. A frequência de insatisfação com a imagem corporal foi alta tanto entre homens (50,9%) como mulheres (78,4%). / Brazil is the second country in number of gym clubs, currently with about 30 thousand units. Despite the transition in the managing model and philosophy of gym clubs from fitness to wellness, many still disseminate the cult of a lean and athletic body, diets without nutritional basis, and uncontrolled consumption of supplements. We have growing evidence that a significant number of individuals going to gym clubs develop an exacerbated commitment to the practice of physical exercises, yielding even pathological dependence. The main goal of our work is to determine the association between exercise dependence (ED), supplements consumption, and dissatisfaction with body image between users of gym clubs. For this purpose we employed the Commitment Exercise Scale (CES) in a sample of 227 gym club users, over 19 years old, from both sexes, in three gym clubs. We used nutritional assesment to determine the profile of supplements consumption, and recorded anthropometrical and exercise engagement data. Frequency of ED in gym clubs was estimated to be 66% with odds ratio of 4.53 favoring supplements consumption. Dependent individuals are on average young, most probably males, attending the gym club more than 5 times a week, consumers of more than on type of supplement, and practitioners of body building. Frequency of body image dissatisfaction is high both between men (50.9%) and women (78.4%).

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2015-02-04T11:11:57Z No. of bitstreams: 2 Dissertação - Angelica Ribeiro Araujo - 2014.pdf: 1233873 bytes, checksum: 9b40d445937726aa9426d3b123936726 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-02-05T14:20:52Z (GMT) No. of bitstreams: 2 Dissertação - Angelica Ribeiro Araujo - 2014.pdf: 1233873 bytes, checksum: 9b40d445937726aa9426d3b123936726 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-02-05T14:20:52Z (GMT). No. of bitstreams: 2 Dissertação - Angelica Ribeiro Araujo - 2014.pdf: 1233873 bytes, checksum: 9b40d445937726aa9426d3b123936726 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-25 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The present study aimed to evaluate the encapsulated butyric acid in the control of Salmonella enterica serovar Enteritidis, performance and systemic health of broiler chickens experimentally inoculated. 576 one-day-old male chicks were distributed in a completely randomized design with eight treatments and six replications each. The poultries were inoculated orally at one-day-old with 0.3 ml of phosphate buffered saline, containing approximately 2.0 x 10 6 CFU/ml of Salmonella enterica serovar Enteritidis. Treatment 1 (T1) was the control group (Placebo); T2 - received butyric acid at a dose of 0.03%; T3 - received butyric acid at a dose of 0.075%; T4 - received the butyric acid at a dose of 0.15%; T5 -group inoculated orally (Positive Control SE); T6 - inoculated orally treated with 0.03%; T7 - inoculated orally treated with 0.075%; T8 - inoculated orally treated with 0.15%. At 22 days of age, the chickens were reinfected with 0.5 ml of phosphate buffered saline containing concentration greater than 1.0 x 10 9 CFU/ml of Salmonella. Butyric acid favored the performance up to 21 days. The acid reduced the intestinal population E. coli. The intestinal pH did not differ by butyric acid, however Salmonella caused a reduction. At 14 days, the acidification effected the growth of the villi of the jejunum and Salmonella caused a reduction in the villous and greater relation villi : crypt in the duodenum and jejunum. No Salmonella was isolated from cloacal swabs collected from poultries that received the dose of 0.03%. Salmonella reduced intestinal weight. The colonization of Salmonella in organs at eight and 28 days of age was reduced in the presence of acid. Liver weight was smaller in the inoculated poultries and larger in the non-inoculated poultries and treated with 0.03% at 15 days. The spleen was smaller than in inoculated poultries which received the dose of 0.03%, at eight days. Salmonella reduced the bursa weight at 15 days.Dietary acidification reduced the lymphoid depletion in the inoculated group. Salmonella influenced the antibody production against Newcastle Disease and Salmonella enterica serovar Enteritidis. The dose of 0.15% increased the antibody production against Newcastle Disease in the inoculated groups and antibodies against Salmonella enterica serovar Enteritidis in the non-inoculated group at 42 days. The mortality of poultries did not differ between treatments. We conclude that, among the investigated dosages, the inclusion of 0.03% yielded the best results in performance and beneficial effects on intestinal health and organ biometrics. The dose of 0.15% improved humor immunity of the poultries. / O presente estudo teve como objetivo avaliar o ácido butírico encapsulado no controle de Salmonella enterica sorovar Enteritidis, desempenho e saúde sistêmica de frangos de corte experimentalmente inoculados. Foram utilizados 576 pintos machos de um dia de idade distribuídos em delineamento inteiramente ao acaso com oito tratamentos e seis repetições cada. As aves foram inoculadas via oral ao primeiro dia de idade com 0,3 mL de solução salina tamponada, contendo aproximadamente 2,0 x 10 6 UFC/mL de Salmonella enterica sorovar Enteritidis. O tratamento 1 (T1) consistiu o grupo controle (Placebo); T2 – recebeu o ácido butírico na dose de 0,03%; T3 – recebeu o ácido butírico na dose de 0,075%; T4 – recebeu o ácido butírico na dose de 0,15%; T5 – grupo inoculado via oral (Controle positivo SE); T6 – inoculado via oral tratado com 0,03%; T7 - inoculado via oral tratado com 0,075%; T8 - inoculado via oral tratado com 0,15%. Aos 22 dias de idade, as aves foram re-inoculadas com 0,5 mL de solução salina tamponada, contendo concentração superior a 1,0 x 10 9 UFC/mL de Salmonella. O ácido butírico favoreceu o desempenho até os 21 dias. O ácido reduziu a população intestinal de E. coli. O pH intestinal não foi influenciado pelo ácido butírico, porém Salmonella promoveu redução. Aos 14 dias, a acidificação influenciou o crescimento das vilosidades do jejuno e Salmonella provocou redução nas vilosidades e maior relação vilo : cripta no duodeno e jejuno. Não foi isolado Salmonella dos suabes de cloaca coletados das aves que receberam a dose de 0,03%. Salmonella reduziu o peso do intestino. A colonização de Salmonella nos órgãos aos oito e 28 dias de idade foi reduzida na presença do ácido. Peso do fígado foi menor nas aves inoculadas e maior nas aves não inoculadas e tratadas com 0,03% aos 15 dias. O baço foi menor nas aves inoculadas que receberam a dose de 0,03%, aos oito dias. Salmonella reduziu o peso da bursa aos 15 dias. A acidificação da dieta reduziu a depleção linfoide no grupo inoculado. Salmonella influenciou a produção de anticorpos contra Doença de Newcastle e Salmonella enterica sorovar Enteritidis. A dose de 0,15% aumentou a produção de anticorpos contra Doença de Newcastle no grupo inoculado e de anticorpos contra Salmonella enterica sorovar Enteritidis no grupo não inoculado aos 42 dias. A mortalidade das aves não diferiu entre os tratamentos. Conclui-se que, dentre as dosagens pesquisadas, a inclusão de 0,03% promoveu os melhores resultados no desempenho e efeitos benéficos sobre a saúde intestinal e biometria de órgãos. A dose de 0,15% melhorou a imunidade humoral das aves.

CO2 sequestration is a promising strategy to reduce the emissions of CO2 concentration in the atmosphere, to enhance hydrocarbon production, and/or to extract geothermal heat. The target formations can be deep saline aquifers, abandoned or depleted hydrocarbon reservoirs, and/or coal bed seams or even deep oceanic waters. Thus, the potential formations for CO2 sequestration and EOR (enhanced oil recovery) projects can vary broadly in pressure and temperature conditions from deep and cold where CO2 can exist in a liquid state to shallow and warm where CO2 can exist in a gaseous state, and to deep and hot where CO2 can exist in a supercritical state. The injection, transport and displacement of CO2 in these formations involves the flow of CO2 in subsurface rocks which already contain water and/or oil, i.e. multiphase flow occurs. Deepening our understanding about multiphase flow characteristics will help us building models that can predict multiphase flow behaviour, designing sequestration and EOR programmes, and selecting appropriate formations for CO2 sequestration more accurately. However, multiphase flow in porous media is a complex process and mainly governed by the interfacial interactions between the injected CO2, formation water, and formation rock in host formation (e.g. interfacial tension, wettability, capillarity, and mass transfer across the interface), and by the capillary , viscous, buoyant, gravity, diffusive, and inertial forces; some of these forces can be neglected based on the rock-fluid properties and the configuration of the model investigated. The most influential forces are the capillary ones as they are responsible for the entrapment of about 70% of the total oil in place, which is left behind primary and secondary production processes. During CO2 injection in subsurface formations, at early stages, most of the injected CO2 (as a non-wetting phase) will displace the formation water/oil (as a wetting phase) in a drainage immiscible displacement. Later, the formation water/oil will push back the injected CO2 in an imbibition displacement. Generally, the main concern for most of the CO2 sequestration projects is the storage capacity and the security of the target formations, which directly influenced by the dynamic of CO2 flow within these formations. Any change in the state of the injected CO2 as well as the subsurface conditions (e.g. pressure, temperature, injection rate and its duration), properties of the injected and present fluids (e.g. brine composition and concentration, and viscosity and density), and properties of the rock formation (e.g. mineral composition, pore size distribution, porosity, permeability, and wettability) will have a direct impact on the interfacial interactions, capillary forces and viscous forces, which, in turn, will have a direct influence on the injection, displacement, migration, storage capacity and integrity of CO2. Nevertheless, despite their high importance, investigations have widely overlooked the impact of CO2 the phase as well as the operational conditions on multiphase characteristics during CO2 geo-sequestration and CO2 enhanced oil recovery processes. In this PhD project, unsteady-state drainage and imbibition investigations have been performed under a gaseous, liquid, or supercritical CO2 condition to evaluate the significance of the effects that a number of important parameters (namely CO2 phase, fluid pressure, temperature, salinity, and CO2 injection rate) can have on the multiphase flow characteristics (such as differential pressure profile, production profile, displacement efficiency, and endpoint CO2 effective (relative) permeability). The study sheds more light on the impact of capillary and viscous forces on multiphase flow characteristics and shows the conditions when capillary or viscous forces dominate the flow. Up to date, there has been no such experimental data presented in the literature on the potential effects of these parameters on the multiphase flow characteristics when CO2 is injected into a gaseous, liquid, or supercritical state. The first main part of this research deals with gaseous, liquid, and supercritical CO2- water/brine drainage displacements. These displacements have been conducted by injecting CO2 into a water or brine-saturated sandstone core sample under either a gaseous, liquid or supercritical state. The results reveal a moderate to considerable impact of the fluid pressure, temperature, salinity and injection rate on the differential pressure profile, production profile, displacement efficiency, and endpoint CO2 effective (relative) permeability). The results show that the extent and the trend of the impact depend significantly on the state of the injected CO2. For gaseous CO2-water drainage displacements, the results showed that the extent of the impact of the experimental temperature and CO2 injection rate on multiphase flow characteristics, i.e. the differential pressure profile, production profile (i.e. cumulative produced volumes), endpoint relative permeability of CO2 (KrCO2) and residual water saturation (Swr) is a function of the associated fluid pressure. This indicates that for formations where CO2 can exist in a gaseous state, fluid pressure has more influence on multiphase flow characteristics in comparison to other parameters investigated. Overall, the increase in fluid pressure (40-70 bar), temperature (29-45 °C), and CO2 injection rate (0.1-2 ml/min) caused an increase in the differential pressure. The increase in differential pressure with increasing fluid pressure and injection rate indicate that viscous forces dominate the multi-phase flow. Nevertheless, increasing the differential pressure with temperature indicates that capillary forces dominate the multi-phase flow as viscous forces are expected to decrease with this increasing temperature. Capillary forces have a direct impact on the entry pressure and capillary number. Therefore, reducing the impact of capillary forces with increasing pressure and injection rate can ease the upward migration of CO2 (thereby, affecting the storage capacity and integrity of the sequestered CO2) and enhance displacement efficiency. On the other hand, increasing the impact of the capillary force with increasing temperature can result in a more secure storage of CO2 and a reduction in the displacement efficiency. Nevertheless, the change in pressure and temperature can also have a direct impact on storage capacity and security of CO2 due to their impact on density and hence on buoyancy forces. Thus, in order to decide the extent of change in storage capacity and security of CO2 with the change in the above-investigated parameters, a qualitative study is required to determine the size of the change in both capillary forces and buoyancy forces. The data showed a significant influence of the capillary forces on the pressure and production profiles. The capillary forces produced high oscillations in the pressure and production profiles while the increase in viscous forces impeded the appearance of these oscillations. The appearance and frequency of these oscillations depend on the fluid pressure, temperature, and CO2 injection rate but to different extents. The appearance of the oscillations can increase CO2 residual saturation due to the re-imbibition process accompanied with these oscillations, thereby increasing storage capacity and integrity of the injected CO2. The differential pressure required to open the blocked flow channels during these oscillations can be useful in calculating the largest effective pore diameters and hence the sealing efficiency of the rock. Swr was in ranges of 0.38-0.42 while KrCO2 was found to be less than 0.25 under our experimental conditions. Increasing fluid pressure, temperature, and CO2 injection rate resulted in an increase in the KrCO2, displacement efficiency (i.e. a reduction in the Swr), and cumulative produced volumes. For liquid CO2-water drainage displacements, the increase in fluid pressure (60-70 bar), CO2 injection rate (0.4-1ml/min) and salinity (1% NaCl, 5% NaCl, and 1% CaCl2) generated an increase in the differential pressure; the highest increase occurred with increasing the injection rate and the lowest with increasing the salinity. On the other hand, on the whole, increasing temperature (20-29 °C) led to a reduction in the differential pressure apart from the gradual increase occurred at the end of flooding.

The major aims of this thesis were to investigate the influence of i) antisense gene location relative to the target gene locus (?????location effect?????), ii) double-stranded RNA (dsRNA) formation, and iii) over-expression of host-encoded proteins on antisense RNA-mediated gene regulation. To test the location effect hypothesis, strains were generated which contained the target lacZ gene at a fixed location and the antisense lacZ gene at various genomic locations including all arms of the three fission yeast chomosomes and in close proximity to the target gene locus. A long inverse-PCR protocol was developed to rapidly identify the precise site of antisense gene integration in the fission yeast transformants. No significant difference in lacZ suppression was observed when the antisense gene was integrated in close proximity to the target gene locus, compared with other genomic locations, indicating that target and antisense gene co-localisation is not a critical factor for efficient antisense RNA-mediated gene suppression in vivo. Instead, increased lacZ down-regulation correlated with an increase in the steady-state level of antisense RNA, which was dependent on genomic position effects and transgene copy number. In contrast, convergent transcription of an overlapping antisense lacZ gene was found to be very effective at inhibiting lacZ gene expression. DsRNA was also found to be a central component of antisense RNA-mediated gene silencing in fission yeast. It was shown that gene suppression could be enhanced by increasing the intracellular concentration of non-coding lacZ RNA, while expression of a lacZ panhandle RNA also inhibited beta-galactosidase activity. In addition, over-expression of the ATP-dependent RNA-helicase, ded1, was found to specifically enhance antisense RNA-mediated gene silencing. Through a unique overexpression screen, four novel factors were identified which specifically enhanced antisense RNA-mediated gene silencing by up to an additional 50%. The products of these antisense enhancing sequences (aes factors), all have natural associations with nucleic acids which is consistent with other proteins which have previously been identified to be involved in posttranscriptional gene silencing.

No description available.

Anonymous communications networks help to solve the real and important problem of enabling users to communicate privately over the Internet. However, by doing so, they also introduce an entirely new problem: How can service providers on the Internet---such as websites, IRC networks and mail servers---allow anonymous access while protecting themselves against abuse by misbehaving anonymous users? Recent research efforts have focused on using anonymous blacklisting systems (also known as anonymous revocation systems) to solve this problem. As opposed to revocable anonymity systems, which enable some trusted third party to deanonymize users, anonymous blacklisting systems provide a way for users to authenticate anonymously with a service provider, while enabling the service provider to revoke access from individual misbehaving anonymous users without revealing their identities. The literature contains several anonymous blacklisting systems, many of which are impractical for real-world deployment. In 2006, however, Tsang et al. proposed Nymble, which solves the anonymous blacklisting problem very efficiently using trusted third parties. Nymble has inspired a number of subsequent anonymous blacklisting systems. Some of these use fundamentally different approaches to accomplish what Nymble does without using third parties at all; so far, these proposals have all suffered from serious performance and scalability problems. Other systems build on the Nymble framework to reduce Nymble's trust assumptions while maintaining its highly efficient design. The primary contribution of this thesis is a new anonymous blacklisting system built on the Nymble framework---a nimbler version of Nymble---called Nymbler. We propose several enhancements to the Nymble framework that facilitate the construction of a scheme that minimizes trust in third parties. We then propose a new set of security and privacy properties that anonymous blacklisting systems should possess to protect: 1) users' privacy against malicious service providers and third parties (including other malicious users), and 2) service providers against abuse by malicious users. We also propose a set of performance requirements that anonymous blacklisting systems should meet to maximize their potential for real-world adoption, and formally define some optional features in the anonymous blacklisting systems literature. We then present Nymbler, which improves on existing Nymble-like systems by reducing the level of trust placed in third parties, while simultaneously providing stronger privacy guarantees and some new functionality. It avoids dependence on trusted hardware and unreasonable assumptions about non-collusion between trusted third parties. We have implemented all key components of Nymbler, and our measurements indicate that the system is highly practical. Our system solves several open problems in the anonymous blacklisting systems literature, and makes use of some new cryptographic constructions that are likely to be of independent theoretical interest.