886 resultados para Systems and Information Theory
Resumo:
The evaluation of technologies employed at the agricultural production system such as crop rotation and soil preparation, both associated with crop-livestock integration, is crucial. Therefore, the aim of the present study was to evaluate the incorporation of lime for three no-tillage systems and cultural managements in system of crop-livestock integration, with emphasis on corn grain yield. The experiment was conducted from January 2003 to April 2005 at Selvíria city, MS, in Dystroferric Red Latosol, clay texture. The experimental design was randomized blocks with split plots consisted of three main treatments, aimed the soil physics conditioning and the incorporation of lime: PD - No-no-tillage; CM - minimum no-tillage, and PC - conventional no-tillage; and of two secondary treatments related to the management: rotation and crop succession, with four replications. Data on agronomic traits of maize were analyzed: plant height, stem diameter, height of the first spike insertion, 100 grains weight and grain yield. The results showed that the maize produced under the system of crop-livestock integration is quite feasible, showing that grain yields are comparable to averages in the region and the different soil physical conditioning and incorporation of lime did not influence the corn yield as well as the cultural managements, rotation and succession, did not affect the maize crop behavior after two years of cultivation.
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ABSTRACT Tractor traveling speed can influence the quality of spraying depending on the application technology used. This study aimed to evaluate the droplet spectrum, the deposition and uniformity of spray distribution with different spraying systems and traveling speeds of a self-propelled sprayer in two phenological stages of the cotton plant (B9 and F13). The experimental design was randomized blocks and treatments were three spraying techniques: common flat spray tips; tilted flat jet with air induction, at 120 L ha-1; and rotary atomizer disk, 20 L ha-1, combined with four traveling speeds: 12, 15, 18 and 25 km h-1, with four replications. Spraying deposition was evaluated for both leaf surfaces from the cotton plant apex and base (stage B9) and middle part of the plant (stage F13) with a cupric marker. A laser particle analyzer also assessed the droplet spectrum. The centrifugal power spray system produces more homogeneous droplet spectrum and increased penetration of droplets into the canopy in both phenological stages. Variation on the operating conditions necessary for increased traveling speed negatively influences the pattern of spraying deposits.
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The objective of this master’s thesis was twofold: first to examine the concept of customer value and its drivers and second to identify information use practices. The first part of the study represents explorative research that was carried out by examining a case company’s customer satisfaction data that was used to identify sales and technical customer service related value drivers on a detailed attribute level. This was followed by an examination of whether these attributes had been commented on in a positive or a negative light and what were the reasons why the case company had received higher or lower ratings than its competitor. As a result a classification of different sales and technical customer service related attributes was created. The results indicated that the case company has performed well, but that the results varied on the company’s business segment level. The case company’s staff, service and the benefits from a long-lasting relationship came up in a positive light whereas attitude, flexibility and reaction time came up in a negative light. The reasons for a higher or lower score in comparison to competitor varied. The results indicated that a customer’s satisfaction with the company’s performance did not always mean that the company was outperforming the competition. The second part of the study focused on customer satisfaction information use from the viewpoints of information access, dissemination and reaction. The study was conducted by running an internal survey among the case company’s staff. The results showed that information use practices varied across the company and some units or teams had taken a more proactive approach to the information use than others.
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Insufficient understanding of entrepreneurial opportunities characterizes entrepreneurship research (Companys & McMullen 2006, 302). Subsequently, the purpose of this study was to analyze the concept of entrepreneurial opportunity and to explore and synthetize the integrated theory of entrepreneurial opportunity. A theoretical and concept analytical approach was adapted. Findings of this study was that entrepreneurial opportunity concept was used for variety of different phenomena. No commonly accepted definition existed. Altogether 24 attributes that described the concept were found. The most frequently attached attributes were agent and action, new goods and services, market, value, new means ends or both, and future. Further, the results implied that opportunity could be best understood as a part of a process. Opportunity emerges out of intervened factors. Changes in the environment together with factors related to knowledge, cognition and social ties are the most important drivers of opportunity. Preventing factors that impeded the emergence of opportunity were typically related to cognitive and organizational factors. This study found a tendency towards more integrated theory of entrepreneurial opportunity. The integrated theory acknowledged the usefulness of both discovery and creation theories of opportunity in explaining opportunity. Yet three argument types of integrating two different opportunity theories were identified. These were process category, contextual category and complementing category. Opportunity is at the same time cognitive, social and linguistic construct, although it is shaped by the objective environment. Opportunity requires linguistic endeavors to become explicit. Materialization of opportunity occurs in a social context. Moreover, it is always characterized by some extent of subjectivity, as opportunities cannot appear without the agent and their action. Due to these the concept remains always to some extent ambiguous. Tolerating and harnessing change and investing in human and social capital create the preeminent environment for the entrepreneurial opportunity to be identified.
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A frequency-domain method for nonlinear analysis of structural systems with viscous, hysteretic, nonproportional and frequency-dependent damping is presented. The nonlinear effects and nonproportional damping are considered through pseudo-force terms. The modal coordinates uncoupled equations are iteratively solved. The treatment of initial conditions in the frequency domain which is necessary for the treatment of the uncoupled equations is initially adressed.
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New microbiological methods have been developed and commercialized, but their performance must be guaranteed. The aim of the present study was to evaluate the PetrifilmTM and TEMPO® systems compared to the conventional method for counting microorganisms in pasteurized milk. A total of 141 samples of pasteurized milk were analyzed by counting mesophilic aerobic, Coliforms at 35 ºC, Coliforms at 45 ºC, and Escherichia coli microorganisms. High correlation was found between the methods for counting Coliforms at 35 ºC, but low correlation was found for counting mesophilic aerobic, Coliforms at 45 ºC, and Escherichia coli. No significant statistical difference was found among the three methods for counting Coliforms at 35 ºC; however, the mean counts of mesophilic aerobic, Coliforms at 45 ºC, and Escherichia coli showed significant statistical difference. PetrifilmTM and TEMPO® systems had satisfactory results for Coliforms at 35 ºC in pasteurized milk but low performance for mesophilic aerobic, Coliforms at 45 ºC and Escherichia coli.
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This research was directed towards the investigation of the Smiles rearrangement in hydrazidic systems and the synthesis of related heterocyclic compounds. The work can be conveniently divided into two main sections. Section 1 of the thesis relates to the synthesis and examination of the O+N migration of phenoxy- derivatives of hydrazidic halides. In general, hydrazidic halides were found to react with 2-nitrophenol and 4-nitrophenol to give corresponding a-nitrophenoxy- compounds. These a-nitrophenoxy- compounds were found to rearrange in warm base to give the corresponding N-benzoyl compounds via a proposed five-membered transition state. Experiments conducted in styrene revealed no radical contribution to the rearrangement. Cross-over product analysis indicated the rearrangement as intramolecular and consistent with the Smiles rearrangement. The preparation of N-a-chlorobenzylidene-N'-2-nitrophenyl- -N'-(2,4-dibromophenyl)hydrazine from N-benzoyl-N'-2-nitrophenyl- N'-(2,4-dibromophenyl)hydrazine was accomplished using phosphorus oxychloride. Examination of this hydrazidic chloride indicated a marked decrease .in reactivity as compared to the N-a-chlorobenzylidene-N'-phenylhydrazine case. Section 2 concerns itself with the preparation of heterocyclic compounds using an analogy of the five-membered transition state present in the Smiles rearrangement of a substituted benzylidene derivatives A new preparation of 2,4-phenyl1,3,4- oxadiazol-S-one using N-benzoyl-N'-phenylhydrazine and ethyl thiochloroformate is reported. Two new preparations of N-a-thiobenzoyl-N'-(2,4-dibromophenylhydrazine are reported using sodium hydrosulfide in conjunction with N-a-bromobenzylidene-N'-(2,4-dibromophenyl)hydrazine in the first, and phosphorus pentasulfide with N-benzoylN'-( 2,4-dibromophenyl)hydrazine in the second. The latter is preferred due to the formation of a sulfide co-product in the former. Two preparations of 2-phenyl-4-(2,4-dibromophenyl)-1,3,4- thiadiazol-S-one are reported using N-thiobenzoyl-N'-(2,4-dibromophenyl) hydrazine and ethyl chloroformate and ethyl thiochloroformate Two rapid and easy preparations of 2-phenyl-4-(2,4-dibromophenyl)- 1,3,4-triazol-S-one are reported using ethyl chloroformate and ethyl thiochloroformate. Sodium cyanate in conjunction with a-aminobenzylidene-N'-(2,4-dibromophenyl)hydrazine also provided 2-phenyl-4-(2,4-dibromophenyl)-1,3,4-triazol-S-one Section 2 concludes with an examination of two possible mechanistic routes to the prepared heterocycles.
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Fifty-six percent of Canadians, 20 years of age and older, are inactive (Canadian Community Health Survey, 200012001). Research has indicated that one of the most dramatic declines in population physical activity occurs between adolescence and young adulthood (Melina, 2001; Stephens, Jacobs, & White, 1985), a time when individuals this age are entering or attending college or university. Colleges and universities have generally been seen as environments where physical activity and sport can be promoted and accommodated as a result of the available resources and facilities (Archer, Probert, & Gagne, 1987; Suminski, Petosa, Utter, & Zhang, 2002). Intramural sports, one of the most common campus recreational sports options available for post-secondary students, enable students to participate in activities that are suited for different levels of ability and interest (Lewis, Jones, Lamke, & Dunn, 1998). While intramural sports can positively affect the physical activity levels and sport participation rates of post-secondary students, their true value lies in their ability to encourage sport participation after school ends and during the post-school lives of graduates (Forrester, Ross, Geary, & Hall, 2007). This study used the Sport Commitment Model (Scanlan et aI., 1993a) and the Theory of Planned Behaviour (Ajzen, 1991) with post secondary intramural volleyball participants in an effort to examine students' commitment to intramural sport and 1 intentions to participate in intramural sports. More specifically, the research objectives of this study were to: (1.) test the Sport Commitment Model with a sample of postsecondary intramural sport participants(2.) determine the utility of the sixth construct, social support, in explaining the sport commitment of post-secondary intramural sport participants; (3.) determine if there are any significant differences in the six constructs of IV the SCM and sport commitment between: gender, level of competition (competitive A vs. B), and number of different intramural sports played; (4.) determine if there are any significant differences between sport commitment levels and constructs from the Theory of Planned Behaviour (attitudes, subjective norms, perceived behavioural control, and intentions); (5.) determine the relationship between sport commitment and intention to continue participation in intramural volleyball, continue participating in intramurals and continuing participating in sport and physical activity after graduation; and (6.) determine if the level of sport commitment changes the relationship between the constructs from the Theory of Planned Behaviour. Of the 318 surveys distributed, there were 302 partiCipants who completed a usable survey from the sample of post-secondary intramural sport participants. There was a fairly even split of males and females; the average age of the students was twenty-one; 90% were undergraduate students; for approximately 25% of the students, volleyball was the only intramural sport they participated in at Brock and most were part of the volleyball competitive B division. Based on the post-secondary students responses, there are indications of intent to continue participation in sport and physical activity. The participation of the students is predominantly influenced by subjective norms, high sport commitment, and high sport enjoyment. This implies students expect, intend and want to 1 participate in intramurals in the future, they are very dedicated to playing on an intramural team and would be willing to do a lot to keep playing and students want to participate when they perceive their pursuits as enjoyable and fun, and it makes them happy. These are key areas that should be targeted and pursued by sport practitioners.
Resumo:
Individuals who have sustained a traumatic brain injury (TBI) often complain of t roubl e sleeping and daytime fatigue but little is known about the neurophysiological underpinnings of the s e sleep difficulties. The fragile sleep of thos e with a TBI was predicted to be characterized by impairments in gating, hyperarousal and a breakdown in sleep homeostatic mechanisms. To test these hypotheses, 20 individuals with a TBI (18- 64 years old, 10 men) and 20 age-matched controls (18-61 years old, 9 men) took part in a comprehensive investigation of their sleep. While TBI participants were not recruited based on sleep complaint, the fmal sample was comprised of individuals with a variety of sleep complaints, across a range of injury severities. Rigorous screening procedures were used to reduce potential confounds (e.g., medication). Sleep and waking data were recorded with a 20-channel montage on three consecutive nights. Results showed dysregulation in sleep/wake mechanisms. The sleep of individuals with a TBI was less efficient than that of controls, as measured by sleep architecture variables. There was a clear breakdown in both spontaneous and evoked K-complexes in those with a TBI. Greater injury severities were associated with reductions in spindle density, though sleep spindles in slow wave sleep were longer for individuals with TBI than controls. Quantitative EEG revealed an impairment in sleep homeostatic mechanisms during sleep in the TBI group. As well, results showed the presence of hyper arousal based on quantitative EEG during sleep. In wakefulness, quantitative EEG showed a clear dissociation in arousal level between TBls with complaints of insomnia and TBls with daytime fatigue. In addition, ERPs indicated that the experience of hyper arousal in persons with a TBI was supported by neural evidence, particularly in wakefulness and Stage 2 sleep, and especially for those with insomnia symptoms. ERPs during sleep suggested that individuals with a TBI experienced impairments in information processing and sensory gating. Whereas neuropsychological testing and subjective data confirmed predicted deficits in the waking function of those with a TBI, particularly for those with more severe injuries, there were few group differences on laboratory computer-based tasks. Finally, the use of correlation analyses confirmed distinct sleep-wake relationships for each group. In sum, the mechanisms contributing to sleep disruption in TBI are particular to this condition, and unique neurobiological mechanisms predict the experience of insomnia versus daytime fatigue following a TBI. An understanding of how sleep becomes disrupted after a TBI is important to directing future research and neurorehabilitation.
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Gowers, dans son article sur les matrices quasi-aléatoires, étudie la question, posée par Babai et Sos, de l'existence d'une constante $c>0$ telle que tout groupe fini possède un sous-ensemble sans produit de taille supérieure ou égale a $c|G|$. En prouvant que, pour tout nombre premier $p$ assez grand, le groupe $PSL_2(\mathbb{F}_p)$ (d'ordre noté $n$) ne posséde aucun sous-ensemble sans produit de taille $c n^{8/9}$, il y répond par la négative. Nous allons considérer le probléme dans le cas des groupes compacts finis, et plus particuliérement des groupes profinis $SL_k(\mathbb{Z}_p)$ et $Sp_{2k}(\mathbb{Z}_p)$. La premiére partie de cette thése est dédiée à l'obtention de bornes inférieures et supérieures exponentielles pour la mesure suprémale des ensembles sans produit. La preuve nécessite d'établir préalablement une borne inférieure sur la dimension des représentations non-triviales des groupes finis $SL_k(\mathbb{Z}/(p^n\mathbb{Z}))$ et $Sp_{2k}(\mathbb{Z}/(p^n\mathbb{Z}))$. Notre théoréme prolonge le travail de Landazuri et Seitz, qui considérent le degré minimal des représentations pour les groupes de Chevalley sur les corps finis, tout en offrant une preuve plus simple que la leur. La seconde partie de la thése à trait à la théorie algébrique des nombres. Un polynome monogéne $f$ est un polynome unitaire irréductible à coefficients entiers qui endengre un corps de nombres monogéne. Pour un nombre premier $q$ donné, nous allons montrer, en utilisant le théoréme de densité de Tchebotariov, que la densité des nombres premiers $p$ tels que $t^q -p$ soit monogéne est supérieure ou égale à $(q-1)/q$. Nous allons également démontrer que, quand $q=3$, la densité des nombres premiers $p$ tels que $\mathbb{Q}(\sqrt[3]{p})$ soit non monogéne est supérieure ou égale à $1/9$.
Resumo:
Dans cette thèse, nous étudions quelques problèmes fondamentaux en mathématiques financières et actuarielles, ainsi que leurs applications. Cette thèse est constituée de trois contributions portant principalement sur la théorie de la mesure de risques, le problème de l’allocation du capital et la théorie des fluctuations. Dans le chapitre 2, nous construisons de nouvelles mesures de risque cohérentes et étudions l’allocation de capital dans le cadre de la théorie des risques collectifs. Pour ce faire, nous introduisons la famille des "mesures de risque entropique cumulatifs" (Cumulative Entropic Risk Measures). Le chapitre 3 étudie le problème du portefeuille optimal pour le Entropic Value at Risk dans le cas où les rendements sont modélisés par un processus de diffusion à sauts (Jump-Diffusion). Dans le chapitre 4, nous généralisons la notion de "statistiques naturelles de risque" (natural risk statistics) au cadre multivarié. Cette extension non-triviale produit des mesures de risque multivariées construites à partir des données financiéres et de données d’assurance. Le chapitre 5 introduit les concepts de "drawdown" et de la "vitesse d’épuisement" (speed of depletion) dans la théorie de la ruine. Nous étudions ces concepts pour des modeles de risque décrits par une famille de processus de Lévy spectrallement négatifs.