996 resultados para Variable frequency oscillators


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PURPOSE: To evaluate the frequency of fear of needles and the impact of a multidisciplinary educational program in women with pre-gestational and gestational diabetes taking insulin during pregnancy. METHODS: The short Diabetes Fear of Injecting and Self-testing Questionnaire (D-FISQ), composed by two subscales that access fear of self injection (FSI) and fear of self testing (FST), was administered twice during pregnancy to 65 pregnant women with pre-gestational and gestational diabetes: at the first endocrine consult and within the last two weeks of pregnancy or postpartum. An organized multidisciplinary program provided diabetes education during pregnancy. Statistical analysis was carried out by Wilcoxon and McNemar tests and Spearman correlation. A p<0.05 was considered to be significant. RESULTS: Data from the short D-FISQ questionnaire shows that 43.1% of pregnant women were afraid of needles in the first evaluation. There was a significant reduction in scores for FSI and FST subscales between the first and second assessments (first FSI 38.5% compared with second 12.7%, p=0.001; first FST 27.7% compared with second FST 14.3%, p=0.012). CONCLUSIONS: The fear of needles is common in pregnant women on insulin therapy and an organized multidisciplinary educational diabetes program applied during pregnancy reduces scores of such fear.

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Transportation of fluids is one of the most common and energy intensive processes in the industrial and HVAC sectors. Pumping systems are frequently subject to engineering malpractice when dimensioned, which can lead to poor operational efficiency. Moreover, pump monitoring requires dedicated measuring equipment, which imply costly investments. Inefficient pump operation and improper maintenance can increase energy costs substantially and even lead to pump failure. A centrifugal pump is commonly driven by an induction motor. Driving the induction motor with a frequency converter can diminish energy consumption in pump drives and provide better control of a process. In addition, induction machine signals can also be estimated by modern frequency converters, dispensing with the use of sensors. If the estimates are accurate enough, a pump can be modelled and integrated into the frequency converter control scheme. This can open the possibility of joint motor and pump monitoring and diagnostics, thereby allowing the detection of reliability-reducing operating states that can lead to additional maintenance costs. The goal of this work is to study the accuracy of rotational speed, torque and shaft power estimates calculated by a frequency converter. Laboratory tests were performed in order to observe estimate behaviour in both steady-state and transient operation. An induction machine driven by a vector-controlled frequency converter, coupled with another induction machine acting as load was used in the tests. The estimated quantities were obtained through the frequency converter’s Trend Recorder software. A high-precision, HBM T12 torque-speed transducer was used to measure the actual values of the aforementioned variables. The effect of the flux optimization energy saving feature on the estimate quality was also studied. A processing function was developed in MATLAB for comparison of the obtained data. The obtained results confirm the suitability of this particular converter to provide accurate enough estimates for pumping applications.

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Tämän pro gradu– tutkielman tavoitteena oli testata täytettyjen taukojen (er ja erm) esiintymistiheyttä, sijaintia kieliopillisessa rakenteessa sekä funktioita Kjellmerin (2003) korpus-tutkimuksessa. Materiaalina käytin viiden yhdysvaltalaisen poliitikon puhetta keskusteluohjelmasta Larry King Live. Tutkimuksessani sovelsin Kjellmerin tutkimusmenetelmiä, joita muokkasin huomattavasti suppeampaan materiaaliini sopiviksi. Lähestymistapani oli täten induktiivinen toisin kuin testatussa tutkimuksessa. Materiaalini oli tarkoituksellisesti rajattu, sillä halusin selvittää, kuvaavatko Kjellmerin laajaan materiaaliin perustuvat tutkimustulokset myös täytettyjen taukojen käyttöä suppeammassa materiaalissa. Materiaalini (kokonaisuudessaan 101 minuuttia) transkriboin ortografisesti. Analyysissäni arvioin täytettyjen taukojen esiintymistiheyden puhujakohtaisesti ja koko ryhmälle suhteuttamalla täytettyjen taukojen lukumäärän kokonaissanamäärään. Tämän jälkeen tein perinteisen kielioppianalyysin rakenteista, joita edeltää tai joissa esiintyy täytetty tauko, ja täytettyjen taukojen sijainnin perusteella luokittelin ne sana-, lauseke-, ja lausetasolle. Lopuksi analysoin täytettyjen taukojen käyttöä soveltaen Kjellmerin ehdottamia funktioita (hesitaatio, vuorottelujäsennyksen merkitseminen, huomion herättäminen ja kontaktin luominen, korostus ja korjaus) ja niiden piirteitä omaan materiaaliini. Tutkimukseni perusteella täytetyt tauot esiintyvät tutkitun viiden poliitikon puheessa suhteellisen usein. Puhujakohtaiset eroavaisuudet olivat kuitenkin huomattavat. Kieliopillisen luokitteluni mukaan sana-, lauseke- ja lausetasot eivät täysin kuvaa täytettyjen taukojen sijoittumista, sillä täytetyt tauot edelsivät mm. määre-lauseita, jotka eivät vastaa lausetasoa englannin kielessä. Materiaalini funktioanalyysi osoitti, että täytetyt tauot yleensä vastaavat yhtä tai useampaa Kjellmerin ehdottamaa funktioita. Lisäksi tutkimukseni mukaan täytetyillä tauoilla on ainakin yksi rakenteellinen funktio. Analyysini perusteella Kjellmerin tutkimustulokset ovat siis pääosin sovellettavissa suppeampaan materiaaliin. Puutteiksi hänen tutkimuksessaan osoittautuivat funktioanalyysille tärkeän kontekstuaalisen informaation puute sekä keskittyminen täytettyihin taukoihin, jotka esiintyvät vain tietyissä kielioppirakenteissa. Yleisesti voin tutkimukseni pohjalta todeta, että täytetyt tauot ovat vielä vajaasti tunnettuja ja että kieliopillisen sijoituksen ja funktioiden lisätutkimus on tarpeellista.

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Risk factors for subclinical mastitis were studied in 474 buffaloes cows proceeding from four dairy farms located in the states of Pernambuco, Alagoas, Bahia and Ceará, Brazil. Milk samples (n=1896) of lactating buffaloes cows were examined for somatic cells count (SCC) and microbiologic exam, and a questionnaire composed by objective questions was applied in order to obtain animals and herd management data. Risk factors analysis was performed in two stages: univariate and mutivariate analysis. Two analysis were performed, one considering the animal classification for SCC as the dependent variable (<400,000 - negative; >400,000 - positive) and another, considering the microbiologic exam result (positive and negative). In the multivariate analysis considering SCC as dependent variable, the lack of teat washing was the only variable identified as a risk factor, so that farms without this procedure before the milking presented risk of infection of 2.68 (I.C. 1.49-4.83). In the multivariate analysis considering the microbiologic exam as dependent variable, it was observed that properties that performed the cleaning of the milking equipment manually presented risk of 1.85 (I.CI. 1.32-3.64), which was higher than those properties that performed the cleaning mechanically (p=0.019). Risk factors for the occurrence of subclinical mastitis in dairy buffaloes in Brazilian Northeast farms were related to the characteristics of improper milking management. Risk factors identified in this study must be carefully corrected in order to reduce the frequency of mastitis cases, and therefore, contribute for disease control and prevention in the herds.

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A case-control study was carried out in litters of 1 to 7-day-old piglets to identify the main infectious agents involved with neonatal diarrhea in pigs. Fecal samples (n=276) from piglets were collected on pig farms in the State of Rio Grande do Sul, Brazil, from May to September 2007. Litters with diarrhea were considered cases (n=129) and normal litters (n=147) controls. The samples were examined by latex agglutination test, PAGE, conventional isolating techniques, ELISA, PCR, and microscopic methods in order to detect rotavirus, bacterial pathogens (Escherichia coli, Clostridium perfringens type A and C, and Clostridium difficile), and parasites (Coccidian and Cryptosporidium spp.). Outbreaks of diarrhea were not observed during sampling. At least one agent was detected in fecal samples on 25 out of 28 farms (89.3%) and in 16 farms (57.1%) more than one agent was found. The main agents diagnosed were Coccidia (42.86%) and rotavirus (39.29%). The main agents identified in litters with diarrhea were Clostridium difficile (10.6%), Clostridium perfringens type A (8.8%) and rotavirus (7.5%); in control litters, Clostridium difficile (16.6%) and Coccidian (8.5%). Beta hemolytic Escherichia coli and Clostridium perfringens type C were not detected. When compared with controls, no agent was significantly associated with diarrhea in case litters. These findings stress the need for caution in the interpretation of laboratorial diagnosis of mild diarrhea in neonatal pigs, as the sole detection of an agent does not necessarily indicate that it is the cause of the problem.

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The study aimed to evaluate the risk factors associated with the frequency of IgG antibodies against Babesia bovis and B. bigemina in cattle in southern Mozambique. Eight hundred and nine serum samples were collected from cattle in three provinces namely Maputo, Gaza and Inhambane, and tested by indirect enzyme-linked immunosorbent assay (i-ELISA) to assess the humoral immune response towards B. bovis and B. bigemina. The chi-square test at 5% significance was used to determine whether there was an association between gender, age and geographic origin of seropositive animals. The overall prevalence was 78.8% (548/695) for B. bovis and 76.0% (528/695) for B. bigemina. The origin of the animals showed a significant association (p<0.05) with seropositivity to both agents, while gender and age was not associated (p>0.05). Maputo province had the highest rate of positive animals, with 93.7% (118/126) for B. bovis and 97.6% (123/126) for B. bigemina. In Gaza province 77.3% (321/415) of the animals were positive for B. bovis and 67.5% (280/415) for B. bigemina, while in the province of Inhambane the levels of seropositivity were 70.8% (109/154) and 81.2% (125/154) for B. bovis and B. bigemina respectively. In the present study, the frequency of cattle positive for B. bovis and B. bigemina was shown to increase among older age groups, suggesting that infection and re-infection persisted even after the primary infection. Thus, this region is considered to be in a state of enzootic stability with regards to B. bovis and B. bigemina.

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Leptospirosis is a worldwide anthropozoonosis that infects livestock, including sheep as the carriers to other animals and humans. The present study aimed to determine the prevalence of Leptospira spp. in sheep from two slaughterhouses in the state of São Paulo, Brazil and its association with epidemiological variables. Serum samples from 182 sheep were evaluated for Leptospira spp. antibodies by microscopic agglutination test (MAT). Results indicated 34/182 (18.68%; CI95% 13.70-24.98%) positive serum samples, mainly to the serovar Copenhageni (17/34; 50%; CI95% 33.99-66.01%). Bacterial growth in the Fletcher medium was detected for 13/34 (38.24%; CI95% 23.87-55.08%) animals, and confirmed by Polymerase Chain Reaction (PCR) and sequencing for only two kidney samples from two animals. Thus, treatment and vaccination of sheep, besides rodent control, can be useful to prevent the infection in the studied region since sheep are important Leptospira spp. carriers, and its transmission to slaughterhouse workers is mainly through the manipulation of visceral tissues.

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This study examines the structure of the Russian Reflexive Marker ( ся/-сь) and offers a usage-based model building on Construction Grammar and a probabilistic view of linguistic structure. Traditionally, reflexive verbs are accounted for relative to non-reflexive verbs. These accounts assume that linguistic structures emerge as pairs. Furthermore, these accounts assume directionality where the semantics and structure of a reflexive verb can be derived from the non-reflexive verb. However, this directionality does not necessarily hold diachronically. Additionally, the semantics and the patterns associated with a particular reflexive verb are not always shared with the non-reflexive verb. Thus, a model is proposed that can accommodate the traditional pairs as well as for the possible deviations without postulating different systems. A random sample of 2000 instances marked with the Reflexive Marker was extracted from the Russian National Corpus and the sample used in this study contains 819 unique reflexive verbs. This study moves away from the traditional pair account and introduces the concept of Neighbor Verb. A neighbor verb exists for a reflexive verb if they share the same phonological form excluding the Reflexive Marker. It is claimed here that the Reflexive Marker constitutes a system in Russian and the relation between the reflexive and neighbor verbs constitutes a cross-paradigmatic relation. Furthermore, the relation between the reflexive and the neighbor verb is argued to be of symbolic connectivity rather than directionality. Effectively, the relation holding between particular instantiations can vary. The theoretical basis of the present study builds on this assumption. Several new variables are examined in order to systematically model variability of this symbolic connectivity, specifically the degree and strength of connectivity between items. In usage-based models, the lexicon does not constitute an unstructured list of items. Instead, items are assumed to be interconnected in a network. This interconnectedness is defined as Neighborhood in this study. Additionally, each verb carves its own niche within the Neighborhood and this interconnectedness is modeled through rhyme verbs constituting the degree of connectivity of a particular verb in the lexicon. The second component of the degree of connectivity concerns the status of a particular verb relative to its rhyme verbs. The connectivity within the neighborhood of a particular verb varies and this variability is quantified by using the Levenshtein distance. The second property of the lexical network is the strength of connectivity between items. Frequency of use has been one of the primary variables in functional linguistics used to probe this. In addition, a new variable called Constructional Entropy is introduced in this study building on information theory. It is a quantification of the amount of information carried by a particular reflexive verb in one or more argument constructions. The results of the lexical connectivity indicate that the reflexive verbs have statistically greater neighborhood distances than the neighbor verbs. This distributional property can be used to motivate the traditional observation that the reflexive verbs tend to have idiosyncratic properties. A set of argument constructions, generalizations over usage patterns, are proposed for the reflexive verbs in this study. In addition to the variables associated with the lexical connectivity, a number of variables proposed in the literature are explored and used as predictors in the model. The second part of this study introduces the use of a machine learning algorithm called Random Forests. The performance of the model indicates that it is capable, up to a degree, of disambiguating the proposed argument construction types of the Russian Reflexive Marker. Additionally, a global ranking of the predictors used in the model is offered. Finally, most construction grammars assume that argument construction form a network structure. A new method is proposed that establishes generalization over the argument constructions referred to as Linking Construction. In sum, this study explores the structural properties of the Russian Reflexive Marker and a new model is set forth that can accommodate both the traditional pairs and potential deviations from it in a principled manner.

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Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii, an obligate intracellular parasite protozoan. A large percentage of animals presents specific antibodies caused by a previous exposition, resulting in a chronic infection. Felides are the definitive hosts and the other warm-blooded animals, including primates, are the intermediate hosts. This study was aimed to determine the prevalence of T. gondii infection in free-living tufted capuchin monkeys (Cebus apella nigritus) from an ecological station located on Mata de Santa Teresa, Ribeirão Preto, SP, Brazil. T. gondii antibodies were analyzed by modified agglutination test (MAT) in serum samples of 36 tufted capuchin monkeys, considering eight as cut-off titer. From the studied animals, 3/36 (8.33%; CI95% 3.0-21.9%) presented T. gondii antibodies, all with titer 32. No significative difference was observed relating to the sex (1/3 male and 2/3 female), and to the age (1/3 young and 2/3 adult) (P>0.05). Thus, these results demonstrate the presence of T. gondii antibodies in primates from São Paulo state.

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From a cross-sectional observational study with convenience samples, 347 blood samples from horses were collected from different physiographic regions, as follows: Santa Catarina Plateau (Santa Catarina State - SC), Médio Paraíba do Sul (São Paulo State - SP and Rio de Janeiro State RJ), Mountainous and Metropolitan regions (Rio de Janeiro State - RJ). Samples were tested for the presence of antibodies (IgG) anti Neorickettsia risticii by indirect immunofluorescence assay (IFA). The frequency obtained in this study corroborates with the ones obtained in the U.S.A., which refers to endemic regions. Fisher's exact test showed significant differences in the number of positive animals between regions, indicating that the probability of an animal becoming infected varies depending on the area. The CI 95% revealed no association between infection and geopolitical space. Moreover, Odds ratio test showed differences of an animal getting infected in different regions. This event could be influenced by the type of treatment used in each area, as the seasonal frequency of injury or even potential vectors. Therefore, there are seropositive animals for N. risticii in the studied areas, suggesting that this agent may be circulating in those regions. Future studies mainly based on molecular analyzes are needed to confirm these serological findings.

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In order to determine auscultatory and electrocardiographic characteristics of Crioulo horses, one hundred animals ranging between one and twenty-six years of age (21 stallions, nine geldings, 27 pregnant mares e 43 not pregnant mares) were evaluated. The cardiac auscultation was performed during the clinical examination of the cardiovascular system, evaluating frequency, rate, normal and abnormal heart sounds (heart murmurs). The electrocardiographic examination followed the bipolar base-apex derivative system with animals at rest, by using an ECG-PC TEB equipment. The cardiac frequency, heart rate, morphology, duration, wave and complex amplitudes and interval durations were determined. The results were submitted to ANOVA and Tukey tests with an error probability of 5%. The cardiac auscultation revealed presence of functional systolic and diastolic murmur (10.00%) and systolic murmur compatible with tricuspid regurgitation besides normal heart sounds S1 (100.0%), S2 (100.0%), S3 (19.0%) and S4 (34.0%). The cardiac frequency obtained the average of 43.64 bpm, observing significative differences in relation to sexual and age factors and training level. The sinus rhythm was the most frequent (57.00%), followed by sinus tachycardia (38.00%) and sinus arrhythmia (5.00%), being observed rhythm disturbances in 16% of tracings. The P and T waves were observed more frequently in their forms P bifida positive (95.00%) and biphasic T (91.00%), being variable at tracing. There were also observed Q waves in 12.00% of the tracings. Thus, it was concluded that the auscultatory characteristics of Crioulo horses are according to the described in the literature for the species and the sexual factor, category, age factor and training level can influence some electrocardiographic parameters.

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This paper describes an electronic transducer for multiphase flow measurement. Its high sensitivity, good signal to noise ratio and accuracy are achieved through an electrical impedance sensor with a special guard technique. The transducer consists of a wide bandwidth and high slew rate differentiator where the lead inductance and stray capacitance effects are compensated. The sensor edge effect is eliminated by using a guard electrode based on the virtual ground potential of the operational amplifier. A theoretical modeling and a calibration method are also presented. The results obtained seem to confirm the validity of the proposed technique.

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The nonlinear interaction between Görtler vortices (GV) and three-dimensional Tollmien-Schlichting (TS) waves nonlinear interaction is studied with a spatial, nonparallel model based on the Parabolized Stability Equations (PSE). In this investigation the effect of TS wave frequency on the nonlinear interaction is studied. As verified in previous investigations using the same numerical model, the relative amplitudes and growth rates are the dominant parameters in GV/TS wave interaction. In this sense, the wave frequency influence is important in defining the streamwise distance traveled by the disturbances in the unstable region of the stability diagram and in defining the amplification rates that they go through.

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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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The use of a robust position controller for a robotic manipulator moving in free space is presented. The aim is to implement in practice a controller that is robust to uncertainties in the model of the system, as well as being inexpensive from a computational point of view. Variable structure theory provides the technique for the design of such controller. The design steps are presented, first from a theoretical perspective and then applied to the control of a two degree-of-freedom manipulator. Simulation results that backed the implementation are presented, followed by the experiments conducted and the results that were obtained. The conclusion is that variable structure control is readily applicable to industrial robots for the robust control of positions.