899 resultados para primary frequency control


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Pós-graduação em Engenharia Elétrica - FEIS

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Saccadic eye movements have been shown to affect posture by decreasing the magnitude of body sway in young adults. However, there is no evidence of how the search for visual information that occurs during eye movements affects postural control in older adults. The purpose of the present study was to determine the influence of saccadic eye movements on postural control in older adults while they stood on 2 different bases of support. Twelve older adults stood upright in 70-s trials under 2 stance conditions (wide and narrow) and 3 gaze conditions (fixation, saccadic eye movements at 0.5 Hz, and saccadic eye movements at 1.1 Hz). Head and trunk sway amplitude and mean sway frequency were measured in both the anterior/posterior (AP) and medial/lateral (ML) directions. The results showed that the amplitude of body sway was reduced during saccades compared with fixation, as previously observed in young adults. However, older adults exhibited similar sway amplitude and frequency in the AP direction under the wide and narrow stance conditions, which is different from observations in young adults, who display larger sway in a narrow stance compared with a wide stance while performing saccades. These results suggest that although older adults are affected by saccadic eye movements by a decrease in the amplitude of body sway, as observed in young adults, they present a more rigid postural control strategy that does not allow larger sway during a more challenging stance condition.

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Objective: To determine current food handling practices, knowledge and beliefs of primary food handlers with children 10 years old and the relationship between these components. Design: Surveys were developed based on FightBac!™ concepts and the Health Belief Model (HBM) construct. Participants: The majority of participants (n= 503) were females (67%), Caucasians (80%), aged between 30 to 49 years old (83%), had one or two children (83%), prepared meals all or most of the time (76%) and consumed meals away from home three times or less per week (66%). Analysis: Descriptive statistics and inferential statistics using Spearman’s rank correlation coefficient (rho) (p<0.05 and one-tail) and Chi-square were used to examine frequency and correlations. Results: Few participants reached the food safety objectives of Healthy People 2010 for safe food handling practices (79%). Mixed results were reported for perceived susceptibility. Only half of the participants (53-54%) reported high perceived severity for their children if they contracted food borne illness. Most participants were confident of their food handling practices for their children (91%) and would change their food handling practices if they or their family members previously experienced food poisoning (79%). Participants’ reasons for high self-efficacy were learning from their family and independently acquiring knowledge and skills from the media, internet or job. The three main barriers to safe food handling were insufficient time, lots of distractions and lack of control of the food handling practices of other people in the household. Participants preferred to use food safety information that is easy to understand, has scientific facts, causes feelings of health-threat and has lots of pictures or visuals. Participants demonstrate high levels of knowledge in certain areas of the FightBac!TM concepts but lacked knowledge in other areas. Knowledge and cues to action were most supportive of the HBM construct, while perceived susceptibility was least supportive of the HBM construct. Conclusion: Most participants demonstrate many areas to improve in their food handling practices, knowledge and beliefs. Adviser: Julie A. Albrecht

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Educational institutions of all levels invest large amounts of time and resources into instructional technology, with the goal of enhancing the educational effectiveness of the learning environment. The decisions made by instructors and institutions regarding the implementation of technology are guided by perceptions of usefulness held by those who are in control. The primary objective of this mixed methods study was to examine the student and faculty perceptions of technology being used in general education courses at a community college. This study builds upon and challenges the assertions of writers such as Prensky (2001a, 2001b) and Tapscott (1998) who claim that a vast difference in technology perception exists between generational groups, resulting in a diminished usefulness of technology in instruction. In this study, data were gathered through student surveys and interviews, and through faculty surveys and interviews. Analysis of the data used Kendall’s Tau test for correlation between various student and faculty variables in various groupings, and also typological analysis of the transcribed interview data. The analysis of the quantitative data revealed no relationship between age and perception of technology’s usefulness. A positive relationship was found to exist between the perception of the frequency of technology use and the perception of technology’s effectiveness, suggesting that both faculty members and students believed that the more technology is used, the more useful it is in instruction. The analysis of the qualitative data revealed that both faculty and students perceive technology to be useful, and that the most significant barriers to technology’s usefulness include faulty hardware and software systems,lack of user support, and lack of training for faculty. The results of the study suggest that the differences in perception of technology between generations that are proposed by Prensky may not exist when comparing adults from the younger generation with adults from the older generation. Further, the study suggests that institutions continue to invest in instructional technology, with a focus on high levels of support and training for faculty, and more universal availability of specific technologies, including web access, in class video, and presentation software. Adviser: Ronald Joekel

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Certain fungi have been found frequently as saprophytes in areas containing large amounts of bird excreta. These fungi have the ability to survive, multiply, and cause disease once they have entered a host. Two of these are Crypto-coccus neoformans and Histoplasma capsulatum. Both may easily become airborne and be disseminated throughout an area by the prevailing winds. C. neo-formans is commonly isolated from the excreta of pigeon habitats, and in turn has been associated with clinical cases of cryptococcosis, while blackbird roosts, harboring H. capsulatum, have been responsible for several outbreaks of histoplasmosis. When either of these fungi have become established in nature, the sites may become foci for infection and epidemics may occur if the sites are disturbed. This has led to investigation of these organisms with respect to: 1) the frequency of isolation of H. capsulatum from the soil beneath blackbird roosts in a histoplasmosis endemic area; 2) the infectivity of undisturbed roosts positive for H. capsulatum; and 3) the effectiveness of chemical decontamination of areas containing C. neoformans or H. capsulatum.

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The class of electrochemical oscillators characterized by a partially hidden negative differential resistance in an N-shaped current potential curve encompasses a myriad of experimental examples. We present a comprehensive methodological analysis of the oscillation frequency of this class of systems and discuss its dependence on electrical and kinetic parameters. The analysis is developed from a skeleton ordinary differential equation model, and an equation for the oscillation frequency is obtained. Simulations are carried out for a model system, namely, the nickel electrodissolution, and the numerical results are confirmed by experimental data on this system. In addition, the treatment is further applied to the electro-oxidation of ethylene glycol where unusually large oscillation frequencies have been reported. Despite the distinct chemistry underlying the oscillatory dynamics of these systems, a very good agreement between experiments and theoretical predictions is observed. The application of the developed theory is suggested as an important step for primary kinetic characterization.

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The development of an electroanalytical method for simultaneous determination of copper and lead ions in sugar cane spirit (cachaca) using carbon paste electrode modified with ascorbic acid and carbon nanotubes (CPE-AaCNT) is described. Squarewave voltammetry (SWV) with anodic stripping was employed, and this technique was optimized with respect to the following parameters: frequency (50 Hz), amplitude (100 mV) and scan increment (9 mV). The analytical curves were linear in the range from 0.0900 to 7.00 mg L-1 for lead and copper. The limits of detection were 48.5 and 23.9 mu g L-1 for lead and copper, respectively. The developed method was applied to the simultaneous determination of copper and lead in five commercial samples of sugar cane spirit. The results were in good agreement with those obtained by F AAS/GF AAS (flame atomic absorption spectrometry/graphite furnace atomic absorption spectrometry) and showed that CPE-AaCNT can be successfully employed in the simultaneous determination of these metals in real sugar cane spirit samples.

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The course of leprosy depends of the host immune response which ranges from the lepromatous pole (LL) to the tuberculoid pole (TT). A comparative study was conducted in 60 patients with the LL and TT The results showed a mean expression of TGF-beta of 339 +/- 99.4 cells/field for TT and of 519.2 +/- 68.2 cells/field for LL. Frequency of apoptosis was 6.3 +/- 1.8 in TT and 14.0 +/- 6.1 in LL. A correlation (p = 0.0251) between TGF-beta and caspase-3 in the LL was found. This finding indicates a role of TGF-beta and apoptosis in the immune response in leprosy. (C) 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

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The proteasome is the primary contributor in intracellular proteolysis. Oxidized or unstructured proteins can be degraded via a ubiquitin-and ATP-independent process by the free 20S proteasome (20SPT). The mechanism by which these proteins enter the catalytic chamber is not understood thus far, although the 20SPT gating conformation is considered to be an important barrier to allowing proteins free entrance. We have previously shown that S-glutathiolation of the 20SPT is a post-translational modification affecting the proteasomal activities. Aims: The goal of this work was to investigate the mechanism that regulates 20SPT activity, which includes the identification of the Cys residues prone to S-glutathiolation. Results: Modulation of 20SPT activity by proteasome gating is at least partially due to the S-glutathiolation of specific Cys residues. The gate was open when the 20SPT was S-glutathiolated, whereas following treatment with high concentrations of dithiothreitol, the gate was closed. S-glutathiolated 20SPT was more effective at degrading both oxidized and partially unfolded proteins than its reduced form. Only 2 out of 28 Cys were observed to be S-glutathiolated in the proteasomal alpha 5 subunit of yeast cells grown to the stationary phase in glucose-containing medium. Innovation: We demonstrate a redox post-translational regulatory mechanism controlling 20SPT activity. Conclusion: S-glutathiolation is a post-translational modification that triggers gate opening and thereby activates the proteolytic activities of free 20SPT. This process appears to be an important regulatory mechanism to intensify the removal of oxidized or unstructured proteins in stressful situations by a process independent of ubiquitination and ATP consumption. Antioxid. Redox Signal. 16, 1183-1194.

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Objective Metabolic syndrome (MetS) is highly prevalent in rheumatic diseases and is recognized as a new independent cardiovascular risk factor. This study was undertaken to determine the clinical significance of MetS in patients with primary antiphospholipid syndrome (APS). Methods Seventy-one primary APS patients and 73 age- and sex-matched healthy controls were included. Serum samples were tested for lipid profile, Lp(a), glucose, insulin, thyroid-stimulating hormone, free T4, erythrocyte sedimentation rate, C-reactive protein level, and uric acid. MetS was defined by the International Diabetes Federation criteria, and insulin resistance was established using the homeostasis model assessment index. Results The prevalence of MetS was 33.8%, and further comparison between primary APS patients with and without MetS revealed that the former had a higher frequency of arterial events (79.2% versus 42.6%; P = 0.003), angina (29.2% versus 2.1%; P = 0.002), and positive lupus anticoagulant antibody (95.8% versus 76.6%; P = 0.049). In addition, primary APS patients with MetS, as expected, had a higher prevalence of cardiovascular risk factors. On multivariate analysis, only MetS was independently associated with arterial events in primary APS. Conclusion Coexistence of primary APS and MetS seems to identify a subgroup of patients with higher risk of arterial events, suggesting that MetS may aggravate existing endothelial abnormalities of primary APS.

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O hipotireoidismo primário adquirido é uma endocrinopatia frequentemente diagnosticada na espécie canina. A terapia consiste na suplementação oral com levotiroxina sódica (L-tiroxina), no entanto vários protocolos terapêuticos têm sido propostos pela literatura, com doses variando 11 a 44µg/kg uma a duas vezes ao dia, visto à grande variabilidade de absorção e meia-vida plasmática do fármaco. Foram estudados 30 cães com hipotiroidismo primário adquirido (13 machos e 17 fêmeas, idade média de 7,9±1,9 anos e peso médio de 19,1±12,6 kg) atendidos no Hospital Veterinário da Universidade Guarulhos (UnG) e no Serviço de Endocrinologia de duas clínicas particulares da cidade de São Paulo (2009-2011), com o objetivo de avaliar a posologia e a frequência de administração da L-tiroxina, mais frequentemente utilizada, capaz de garantir um controle terapêutico satisfatório, avaliado através dos sinais clínicos e do teste pós-tiroxina, além de correlacionar a dose de tiroxina empregada com o peso dos animais. A dose média de tiroxina utilizada em nossa casuística foi de 16,9±3,1µg/kg, sendo a frequência de administração a cada 12 horas em 50% dos casos. Para se investigar uma possível correlação entre o peso e a dosagem de tiroxina utilizada, uma vez que cães de pequeno porte apresentam maior taxa metabólica que cães de grande porte, os animais foram agrupados em grupo A, cães com peso <10 Kg (n=12/30; 7,7±2,1 kg) e grupo B, cães com peso >10 kg (n=18/30, 26,8±10,7 kg). A dose média de tiroxina empregada nos grupos A e B não apresentaram diferença estatística e foram, respectivamente, 16±3µg/kg e 17±3µg/kg. A frequência de administração foi 50% a cada 24 horas e 50% a cada 12 horas para ambos os grupos. Dessa forma, a dose de tiroxina não parece se correlacionar com o peso do animal, sendo imprevisível quem deverá receber dose e frequência máxima da medicação. O protocolo deve ser individualizado e o paciente devidamente monitorado.

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Objective. The aim of this study was to investigate the orofacial complaints and characteristics of patients with fibromyalgia syndrome (FS) compared with controls. Study Design. We evaluated 25 patients diagnosed with FS compared with 25 gender-and age-matched controls by using a detailed clinical protocol for orofacial pain diagnosis and dental examination. Results. FS patients had a higher frequency of temporomandibular disorders (TMD), masticatory complaints, pain with mandibular movements, and pain upon palpation of the head and neck area. There were no significant differences related to the dental exam. Conclusions. Orofacial complaints including TMD may be present either as symptoms of FS or as a comorbidity associated with this condition. A comprehensive evaluation of patients with FS is necessary to identify the need for specific treatments for orofacial complaints. Future studies, especially those with longitudinal design, should clarify whether a cause-effect relationship exists between orofacial complaints and fibromyalgia. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:e29-e34)

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Loss of Y-chromosome has been correlated with older age in males. Furthermore, current evidence indicates that Y-chromosome loss also occurs in several human tumors, including head and neck carcinomas. However, the association between Y nullisomy and the occurrence of neoplasias in elderly men has not been well established. In the present study, the association between Y-chromosome loss and head and neck carcinomas was evaluated by comparison to cells from peripheral blood lymphocytes and normal mucosa of cancer-free individuals matched for age using dual-color fluorescence in situ hybridization. Twenty-one patients ranging in age from 28 to 68 years were divided into five-year groups for comparison with 16 cancer-free individuals matched for age. The medical records of all patients were examined to obtain clinical and histopathological data. None of the patients had undergone radiotherapy or chemotherapy before surgery. In all groups, the frequency of Y-chromosome loss was higher among patients than among normal reference subjects (P < 0.0001) and was not age-dependent. These data suggest that Y-chromosome loss is a tumor-specific alteration not associated with advanced age in head and neck carcinomas.

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This descriptive epidemiological study analyzed the coordination of tuberculosis (TB) patient care in primary healthcare services according to 23 patients, 16 professionals, and 17 administrators from Ribeirao Preto, Sao Paulo, using an instrument adapted to evaluate TB. According to the informants, the coordination of healthcare provided to patients under the treatment of the Tuberculosis Control Program team was considered satisfactory; however, when there is a need to refer the patient to other care units there are weak points in the coordination of healthcare, which include: interruption of communication flow; and patients' incipient participation in the care process, with a need to increase the sense of responsibility for patient care and encourage patients to become active agents in the process.