As aplicações envolvendo confinamento e aceleração de feixes de partículas carregadas em canais lineares são inúmeras em diversas áreas do conhecimento. A evolução da engenharia dos aceleradores lineares de partículas de próxima geração está fortemente condicionada ao melhor entendimento de fenômenos não-lineares como a formação de halo, inerentes aos atualmente cada vez mais perscrutados regimes de alta densidade de carga e energia. O presente trabalho visa investigar e caracterizar os aspectos dinâmicos e de equilíbrio envolvidos na transição de um feixe ultra-intenso de partículas com mesma carga de um estado inicial não-estacionário para um final estacionário. A alta densidade de partículas implica que as forças repulsivas naturais neste tipo de sistema sejam imprescindíveis para a sua correta descrição. O feixe em questão evolui em um canal linear encapsulado por um duto circular condutor e é focalizado por um campo magnético constante axial de origem solenoidal. Tal feixe inicialmente encontra-se perfeitamente alinhado com o eixo de simetria do sistema de confinamento magnético, sendo, portanto, as oscilações de sua centróide inexistentes. Por simplicidade, foi imposto também ao feixe o vínculo de simetria azimutal. Como condição inicial, considerou-se o estado não-estacionário do feixe descrito por uma densidade homogênea e outra não-homogênea. No primeiro caso, o descasamento e, no segundo, a magnitude da não-homogeneidade são os fatores precursores da instabilidade inicial que conduz o feixe ao estado de equilíbrio. Para ambos os casos, modelos foram desenvolvidos para determinar quantidades dinâmicas, relacionadas à escala de tempo característica da instabilidade inicial, e de equilíbrio, tais como a emitância e o envelope, grandezas estatísticas estas usualmente de interesse em Física de Feixes. Os resultados obtidos foram comparados com simulações numéricas autoconsistentes e o acordo foi satisfatório. Os modelos demonstraram-se eficientes não somente em prever tais quantidades de interesse como também em elucidar aspectos físicos fundamentais intrínsecos ao comportamento observado nas simulações numéricas autoconsistentes e experimentos. / Applications involving confinement and acceleration of charged particle beams in linear channels are innumerous in many fields of the knowledge. The engineering evolution of next-generation particle linear accelerators is strongly conditioned to the better understanding of nonlinear phenomena like halo formation, inherent to the more and more currently explored regimes of high charge density and energy. The present work aims at investigating and characterizing dynamical and equilibrium aspects involved in the transition of a high-intensity beam of charged particles from an initial non-stationary state to a final stationary state. High particle densities mean that the repulsive forces naturally present in these kinds of systems are essential to their adequate description. The beam under analysis evolves inside a linear channel encapsulated by a circular conductor pipe, and is focalized by a constant axial magnetic field generated by solenoids. Such beam is initially perfectly aligned to the symmetry axis of the magnetic confinement system, being in this way its centroid oscillations non-existent. For simplicity, it has been imposed to the beam the constraint of azimuthal symmetry. As initial condition, the beam non-stationary state has been described by a homogeneous and an inhomogeneous particle density. In the first case, the mismatch and, in the second one, the magnitude of inhomogeneity, are the factors forerunner of the initial instability, which leads the beam to evolve to the equilibrium state. For both cases, models have been developed to determine dynamical quantities, related to the characteristic time scale of the initial instability, and equilibrium quantities, such as the emittance and envelope, usually of interest in Beam Physics. The obtained results have been compared with full self-consistent N-particle beam numerical simulations and the agreement has been reasonable. The models have shown to be efficient not only to predict beam quantities of interest as well as to elucidate fundamental physical aspects intrinsic to the behavior observed in the self-consistent numerical simulations and experiments.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-04-18T13:02:05Z No. of bitstreams: 1 Joao Paulo Rodrigues da Silva.pdf: 4322694 bytes, checksum: 73622fb6c482c2976842cc2ad9b5745a (MD5) / Made available in DSpace on 2017-04-18T13:02:05Z (GMT). No. of bitstreams: 1 Joao Paulo Rodrigues da Silva.pdf: 4322694 bytes, checksum: 73622fb6c482c2976842cc2ad9b5745a (MD5) Previous issue date: 2015-10-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The use of tolerant to salinity cultivars and techniques that promotes good agricultural yields in saline soils is important. The objective was to evaluate the activation of defense responses to salt stress induced by halo-priming in plant cowpea cultivars, coming from pre-conditioned seeds. The experiment was carried out in randomized completely design in a greenhouse in a factorial 3x4 and 2x3x3, with three repetitions. The plot was represented by a pot, size 3 dm3, with one plant per pot. Were used two (2) levels salinity: E0, with 0 mmol NaCl and E1 with 60 mmol NaCl in the nutrient solution; three (3) halo-priming levels: HP0, no priming, HP1 immersion in solution with 30 mmol NaCl for 2 hours and HP2, immersion in 60 mmol NaCl for 2 hours; and four (4) cultivars, C1: Canapu, C2: Epace 10; C3: IPA 206 and C4: IPA Miranda 207. The treatment salt stress (E1) started 20 days after planting. They were made germination index evaluation (GI) and emergence speed index (ESI), before the start of the salt stress treatments. After the salt stress treatments, at 60 days after planting, the following biometric evaluations (plant height, stem diameter, dry weight of shoot and root dry weight), percentage reduction evaluation of shoot and chemical evaluations of sodium and potassium. Statistical analysis was done using analysis of variance and average comparison tests, using the electronic program SISVAR. Better results were seen for germination speed index in the Miranda IPA 207 and IPA 206 cultivars when subjected to halo-priming. The height of the main branch was significantly reduced in salt stress situation. The treatments with the presence of halo-priming increased the average stem diameter in Epace 10 and IPA 206 cultivars. The halo-priming with 30 mmol of NaCl for 2 hours significantly increased the root dry weight of cultivars. For dry weight of shoots to grow Canapu had the highest average under salt stress and absence of halo-priming. To the sodium content in the plant, best responses were observed when using the halo-priming 30 mmol NaCl. To the potassium content to cultivate Canapu showed better responses when used halo-priming 60 mmol NaCl. Conclude that the cultivar Canapu is moderately tolerant to irrigation water with salt concentration of 60 mmol NaCl in the vegetative phase. The halo-priming with a concentration of 30 mmol of NaCl can be given to remediate the salt stress in cultivating Canapu. / O emprego de cultivares tolerantes ao estresse salino e de tecnologias que favoreçam bons rendimentos agrícolas em solos salinos são importantes. O objetivo do trabalho foi avaliar a ativação de respostas de defesa, frente ao estresse salino, induzidas por halo-priming em plantas de cultivares de feijão-caupi, oriundas de sementes pré-condicionadas. O experimento foi montado em delineamento inteiramente casualisado, em casa de vegetação, em esquema fatorial 3x4 e 2x3x3, com 3 repetições. A parcela foi representada por um vaso, volume de 3 dm3, com uma planta por vaso. Foram utilizados dois (2) níveis de salinidade: E0, sem NaCl e E1, com 60 mmol de NaCl na solução nutritiva; três (3) níveis de halo-priming: HP0, ausência de priming, HP1 imersão em solução com 30 mmol NaCl por 2 horas e HP2, imersão em 60 mmol NaCl por 2 horas; e quatro (4) cultivares, C1 Canapu, C2 EPACE 10, C3 IPA 206 e C4 Miranda IPA 207. O tratamento salino (E1) foi iniciado 20 dias após o plantio. Foram feitas avaliações de índice de germinação (IG) e índice de velocidade de emergência (IVE), antes do início dos tratamentos salinos. Após tratamentos salinos, aos 60 DAP, foram feitas avaliações biométricas (altura de planta, diâmetro do caule, massa seca da parte aérea e massa seca de raiz), avaliação de redução percentual de MSPA e avaliações químicas (teores de Sódio e Potássio). Foi feita análises de variância e teste de comparação de média, com utilização do programa eletrônico SISVAR. Plantas das cultivares Miranda IPA 207 e IPA 206, oriundas de halo-priming, obtiveram melhores respostas para IVE. A altura do caule foi reduzida significativamente em situação de estresse salino. Para diâmetro do caule, em condições de estresse salino, foi observada redução da média, nas plantas oriundas de pré-condicionamento halo-priming. Nas plantas cultivadas em condições de estresse, oriundas do halo-priming 30 mmol de NaCl, foi observado menor média para MSR e entre as cultivares a IPA 206, teve maior média. Para massa seca da parte aérea, na condição de estresse salino e ausência de halo-priming, foi observado maior média na cultivar Canapu, comprovando sua tolerância ao estresse salino. Para os teores de sódio na planta, foram observadas melhores respostas quando utilizado o halo-priming de 30 mmol de NaCl. Para o teor de potássio, a cultivar Canapu apresentou melhores respostas quando utilizado o halo-priming de 60 mmol NaCl. Conclui-se que a cultivar Canapu é moderadamente tolerante à água de irrigação com concentração salina de 60 mmol de NaCl na fase vegetativa. O halo-priming com concentração de 30 mmol de NaCl pode ser indicado para remediar o estresse salino na cultivar Canapu.

The 3-dimensional structural complexity of coral reef environments is positively correlated with measurements of biodiversity and biomass. EcoReefs are a type of artificial reef that resemble branching corals, such as Acropora cervicornis, which provide an environment of high structural diversity, and that are effective at recruiting and sustaining fish populations. Little is known, however, about the effects of EcoReefs on the surrounding environments in which they are deployed, so this study examined the results after installing Ecoreef modules in a seagrass environment. The installation occurred in March 2009 at Coco Cay in the Berry Island chain in the Bahamas and data was taken over the next two years to compare changes on Ecoreef deployment sites (experimental sites) to sites with no EcoReefs (control sites) and also an older and larger installation with both EcoReefs and Reefballs (Old Reef) that dates back to 2004. Two main categories of information were collected: at the same time (a) the changes in growth of two types of seagrass, Thalassia testudinum and Syringodium filiforme, and (b) the changes in fish populations in and around the EcoReef installations. Experimental sites consisted of 3 groups, 30-35 metres apart, each of 12 EcoReef modules in seagrass beds off the east side of the island. Both seagrass and fish data were collected within the module groups and also for the area 1 metre around the installation to see if there were any “halo” effects, i.e. where seagrass around a reef is cleared by resident fish populations. Seagrass measurements including direct measurements of blade length, width, percentage of epiphytic fauna, and the percentage of dead tissue on each blade were collected. Seagrass coverage was also estimated using a photographic technique. Fish counts were performed using a modified Bohnsack-Bannerot visual survey method, and augmented with transect counts. The results for seagrass indicated that there were some seasonal changes in growth and coverage. Fish populations accumulated rapidly on the Ecoreef modules: at the first-post installation collection data period 4 month later the experimental site fish populations were between 30 and 153 individuals, and remained at this level throughout the study, with a mean population per site of 84.4 individuals over the length of the study. Over the study period it was found that the majority of the fish (67%) on the experimental sites were haemulid, and scarid juveniles of less than 5 cm in length, in contrast to the older and larger mixed reef that had 73% above 5cm, including a stable population of 184 (+/- 24.5) grunts. The older site also had a distinct halo zone of cleared and cropped seagrass, whereas no halo zone was visible at the experimental or control sites, suggesting that the abundance and size of the fish establish and maintain this zone. The results from this study suggest that EcoReefs modules foster fish populations and cause changes in seagrass length, but do not result in the formation of a halo zone directly; the formation of this zone, where present, is likely the result of the fish species that settle on these structures.

So often in astronomy, an object is not considered for its individual merits, but for what we may learn from its properties regarding some larger population. The existence of dark matter is a prime example of this; we cannot see it directly but we can infer its presence by noting its effects on the stars orbiting within its potential. This thesis describes how various sets of tracer populations can be used to probe the properties of a variety of galaxies in the Local Group. I begin by describing the extraction of a variable catalogue from the Sloan Digital Sky Survey Stripe 82 dataset and then use the catalogue to select a high-quality set of RR Lyrae stars. Analysing the distribution of the RR Lyraes reveals three significant substructures in the Milky Way halo: the Hercules-Aquila Cloud and the Sagittarius Stream, which were already known to exist, and the Pisces Overdensity, which was previously undetected. It is a faint, extended structure found at ~80 kpc and is of unknown origin. Altogether, I find that nearly 80% of the RR Lyraes are associated with substructures, consistent with the theory that galaxy halos are predominantly, or even entirely, made up from disrupted satellites. I also investigate the density distribution of RR Lyraes in the halo, finding that it is best fit by a broken-power-law model, in good agreement with previous work. I go on to develop a set of tracer mass estimators that build on previous work which make use of actual (and not projected) distance and proper motion data, reflecting the amount and quality of data now available to us. I show that proper motion data is, in theory, very useful and can greatly increase the accuracy of the mass estimates; in practice, however, current analysis is hampered by the large errors inherent in the proper motion data. The results are also subject to mass-anisotropy degeneracy, which current data is not yet able to break. Nevertheless, I am able to estimate the mass of the Milky Way to be M = 2.7 ± 0.5 x 10¹² Msun and the mass of M31 to be M = 1.5 ± 0.4 x 10¹² Msun. Andromeda XII and Andromeda XIV are two M31 satellites that have been dubbed 'extreme' and are thought to be on first infall into the M31 system. I modify the classical Timing Argument so that it can be applied to two external galaxies and then apply it to M31 and each of And XII and And XIV in turn to investigate the properties of their orbits. I then run a series of Monte Carlo simulations to investigate how likely such satellites are to exist and conclude that they are not as unusual as previously believed. Finally, I discuss three upcoming wide-field, all-sky surveys and their implications for the future of the study of the Local Group.

Here, we present the results from our analysis of 6 yr of optical photometry taken by the Siding Spring Survey (SSS). This completes a search for periodic variable stars within the 30 000 deg(2) of the sky covered by the Catalina Surveys. The current analysis covers 81 million sources with declinations between -20 degrees. and -75 degrees. with median magnitudes in the range 11 < V < 19.5. We find approximately 34 000 new periodic variable stars in addition to the similar to 9000 RR Lyrae that we previously discovered in SSS data. This brings the total number of periodic variables identified in Catalina data to similar to 110 000. The new SSS periodic variable stars mainly consist of eclipsing binaries, RR Lyrae, LPVs, RS CVn stars, delta Scutis, and Anomalous Cepheids. By cross-matching these variable stars with those from prior surveys, we find that similar to 90 per cent of the sources are new discoveries and recover similar to 95 per cent of the known periodic variables in the survey region. For the known sources, we find excellent agreement between our catalogue and prior values of luminosity, period, and amplitude. However, we find many variable stars that had previously been misclassified. Examining the distribution of RR Lyrae, we find a population associated with the Large Magellanic Cloud (LMC) that extends more than 20 degrees from its centre confirming recent evidence for the existence of a very extended stellar halo in the LMC. By combining SSS photometry with Dark Energy Survey data, we identify additional LMC halo RR Lyrae, thus confirming the significance of the population.

The presence of dark matter is inferred at scales ranging from rotations of galaxies to imprints in the CMB – the Big Bang after-glow. The nature of dark matter is, however, still unknown as no detection other than the gravitational one has been made. This thesis presents two analyses searching for a neutrino signal from dark matter annihilations in the Milky Way. The first analysis searched for an excess of νμ charged current events with directions from the central region of the dark matter halo and, was focused on low energy events, thus probing low dark matter particle masses. Approximately 319 days of data collected with the 79-string configuration of the IceCube detector was used in the analysis. Despite a large deficit in the number of observed events the data were found to be consistent with background and upper limits were set on &lt;σⱴ&gt;. At the time of the analysis these limits were the strongest set by a neutrino experiment below 100 GeV. The second analysis was performed on a data sample originally used in an unfolding analysis of the atmospheric and astrophysical neutrino spectra. The data consisted of contained cascade events above 1 TeV collected with the 79-string configuration and the completed detector in the 86-string configuration during two years of data-taking. The limits set by this analysis were more constraining by up to a factor of 10 compared to previous IceCube analyses, and the most competitive limits are set assuming a Burkert halo profile. These two analyses prompted the development of a signal subtraction likelihood method to address the problem of signal contamination in background estimates based on scrambled data. Additionally a study concerning future extensions of IceCube in the Gen2 project is presented. The cascade reconstruction performance was examined and compared for different proposed detector extensions.

Perception plays an important role in the human assessment process. This construction of an image is based on many factors, including race, religion, national origin, income, gender, marital status - in short, the summation of our life experiences. An important consideration for the methodology consumers utilize for purchase decisions has been also referred to as the "Country of Origin" (COO) effect. This individual bias based on perceptions and attitudes has a significant impact on how consumers make their purchasing decisions. The 2008 Farm Bill legislation contained a requirement for country of origin labeling (COOL) for beef, lamb, pork, and other products. This paper examined some of the 2008 Farm Bill's impact on consumer's purchasing decisions regarding beef and related meat protein products. Of a potential population of over 700 respondents, 161 responses were received. Correspondence analysis and preferences indicated by the respondents were used to analyze the results. Respondents were mostly well educated, white, in higher income brackets, and split about 60%-40% between male and female. Food safety is considered important and respondents generally believe that the US food supply is safe. Over 40% of respondents had no knowledge of COOL and its background, but about 70% of respondents believed that COOL should be mandatory for all meat products studied. The majority of respondents (111 of 161) indicated that they would be willing to pay $0.25 to $1.00 per pound more for COOL. However when asked about the likeliness to pay, 25%-30% indicated that they were "Not at all Likely" or "Somewhat Likely" to pay. The correspondence analysis results indicated that beef was a product eaten more often, but considered expensive. Chicken was eaten more often and considered inexpensive and healthful. Turkey was a product considered healthful and inexpensive. Lamb was considered expensive, while pork was inconclusive in the two dimensions used. The results of this study provide information for producers, purveyors, retailers, and the government on the importance of COOL as perceived by consumers, and their willingness to pay for this labeling.

Novel biocatalysts are highly demanded in the white biotechnology. Hence, the development of highly stable and enantioselective biocatalysts with novel functionalities is an ongoing research topic. Here, an osmium ligating single-site ArM was created based on the biotinstreptavidin technology for the dihydroxylation of olefins. For the creation of the artificial catalytic metal center in the streptavidin (SAV) cavity, efficient osmium tetroxide (OsO4) chelating biotin-ligands were created. The unspecific metal binding of the host scaffold was diminished through genetical and chemical modification of the host protein. The created single-site OsO4 chelating ArM was successfully applied in the asymmetric cyclopropanation, revealing a stable and tunable catalytic hybrid system for application. The structural analysis of protein-ligand complexes is essential for the advanced rational design and engineering of artificial metalloenzymes. In previous studies, a SAV-dirhodium ArM was created and successfully applied in the asymmetric cyclopropanation reaction. To improve the selectivity of the SAV-dirhodium complex, the structural location of the organometallic complex in the SAV cavity was targeted and small-angle x-ray scattering (SAXS) was used to obtain the structural information. The SAXS analysis revealed valuable information of the molecular state of the complexes; hence, the method proved to be useful for the structural analysis of protein-ligand interactions. The discovery of novel enzymes from nature is still the major source for improved biocatalysts. One of the most important enzymes used in the molecular biology are DNA polymerases in PCR reactions. The halothermophilic brine-pool 3 polymerase (BR3 Pol) from the Atlantis II Red Sea brine pool showed optimal activities at 55 °C and salt concentrations up to 0.5 M NaCl, and was stable at temperatures above 95 °C. The comparison with the hyperthermophilic KOD polymerase revealed the haloadaptation of BR3 Pol due to an increased negative electrostatic surface charge and an overall higher structural flexibility. Engineered chimeric KOD polymerases with swapped single BR3 Pol domains revealed increased salt tolerance in the PCR, showing increased structural flexibility and a local negative surface charge. The understanding of the BR3 Pol haloadaptation might enable the development of a DNA polymerase tailored for specific PCR reactions with increased salt concentrations.

No description available.

Using archival Far Ultraviolet Spectroscopic Explorer (FUSE) and Hubble Space Telescope (HST) data, we have assembled a survey of eight sight lines through high-velocity cloud Complex C. Abundances of the observed ion species vary significantly for these sight lines, indicating that Complex C is not well characterized by a single metallicity. Reliable metallicities based on [O I/H I] range from 0.1 to 0.25 Z⊙. Metallicities based on [S II/H I] range from 0.1 to 0.6 Z⊙, but the trend of decreasing abundance with H I column density indicates that photoionization corrections may affect the conversion to [S/H]. We present models of the dependence of the ionization correction on H I column density; these ionization corrections are significant when converting ion abundances to elemental abundances for S, Si, and Fe. The measured abundances in this survey indicate that parts of the cloud have a higher metallicity than previously thought and that Complex C may represent a mixture of " Galactic fountain " gas with infalling low-metallicity gas. We find that [S/O] and [Si/O] have a solar ratio, suggesting little dust depletion. Further, the measured abundances suggest an overabundance of O, S, and Si relative to N and Fe. The enhancement of these α-elements suggests that the bulk of the metals in Complex C were produced by Type II supernovae and then removed from the starforming region, possibly via supernova-driven winds or tidal stripping, before the ISM could be enriched by N and Fe.