16 resultados para Fractional Order Integrator
em Scielo Saúde Pública - SP
Resumo:
Is it possible to talk about the rise of a new global (dis)order founded on the challenges posed by environmental issues? Through the review of the state of the art on the subject, this article analyzes the growing importance of the environment, and natural resources in particular, in international relations; and aims to raise awareness among International Relations scholars to the potential positive impact of the development of the discipline in integration with global environmental change studies.
Resumo:
Abstract The European Union (EU) is one of the world´s leading donors in official development assistance (ODA) to give a strong weight in the relationship with recipient partner countries, in particular with those that are more dependent on it. Besides the material weight of its funding, the EU has retained historical ties and influence in diplomatic, political and economic terms in many of its ODA recipient partner countries (particular in Sub-Saharan Africa). Since the 2000s, the EU development policy has not only undergone major structural changes in its institutional framework but also has started to face a new international aid scenario. This paper explores why a normative-based EU development policy is being challenged by reformed EU institutions and a new global order, and how the EU is attempting to respond to this context in face of the deepest recession since the end of the Second World War.
Resumo:
The reproductive biology of Aspidoras fuscoguttatus Nijssen & Isbrücker, 1976 from a stream in São José do Rio Preto, northwestern São Paulo State, Brazil, was monthly investigated in the period of August 1999 to July 2000. Measurements of total length, body weight, gonadal weight and macroscopic assessment of gonadal maturation were performed. Environmental parameters were considered in order to verify associations with the reproductive period. Populational structure showed total length amplitude between 14.2 and 50.8 mm. Pronounced sexual dimorphism was verified. The largest mean values of gonadosomatic relation for females coincided with the rainy season (November to March). Mean length at first sexual maturity was different for males (30.5 mm) and females (37.1 mm). Fecundity varied between 51 and 166 oocytes. Gonadal maturation curve, frequency of maturation stages and size frequency distributions of oocytes in mature ovaries revealed a long reproductive period, suggesting fractional spawning.
Resumo:
Study of the mayfly order Ephemeroptera (Insecta) in Brazil: a scienciometric review. Despite an increase in the number of studies in recent years of the aquatic insect order Ephemeroptera (the mayflies) much still remains to be learnt. In order to identify the current state of knowledge of this group in Brazil, we performed a scienciometric analysis with the purpose of identifying the strong and weak points of Brazilian research into the group. Our research used the "Institute for Scientific Information - ISI" database and was based on the abstracts, titles and keywords of manuscripts published between 1992 and 2011. We selected the papers with the combination of the words "Ephemeroptera" and "Brazil*" based on a search in February 2012. We analyzed 92 articles, and noted a lack of studies in some Brazilian states, no specific studies about some families, and an absence of phylogenetic studies. To improve ecological studies, it is necessary to fine-tune taxonomic resolution. Moreover, there is a lack of studies investigating the environmental variables which influence the distribution of mayflies. Despite these gaps, if the rate of publication with mayflies proceeds at the same pace, we anticipate that many of these knowledge gaps will be closed.
Resumo:
The effect of operational variables and their interaction in TPR profiles was studied using a fractional factorial experimental design. The heating rate and the reducing agent concentration were found to be the most important variables determining the resolution and sensitivity of the technique. They showed opposite effects. Therefore, they should be manipulated preferentially in order to obtain optimized TPR profiles. The effect of sample particle size was also investigated. The tests were carried out within a Cu/Zn/Al2O3 catalyst used for the water-gas shift reaction that presented two distinct species of Cu2+ in TPR profiles.
Resumo:
Starting from zero-, first-, and second-order integrated laws for chemical kinetics, some cases are shown which produce fractional orders. Taking the Michaelis-Menten mechanism as a first example, it is shown that substrate order can go from 1 to zero, depending on relative concentration of enzyme and substrate. Using other examples which show fractional orders higher than one and even negative (inhibition), it is shown that the presence of an equilibrium before or parallel to the rate determining step can be the reason for fractional orders, which is an indication of a more complex mechanism.
Resumo:
The bioassay, first order derivative UV spectrophotometry and chromatographic methods for assaying fluconazole capsules were compared. They have shown great advantages over the earlier published methods. Using the first order derivative, the UV spectrophotometry method does not suffer interference of excipients. Validation parameters such as linearity, precision, accuracy, limit of detection and limit of quantitation were determined. All methods were linear and reliable within acceptable limits for antibiotic pharmaceutical preparations being accurate, precise and reproducible. The application of each method as a routine analysis should be investigated considering cost, simplicity, equipment, solvents, speed, and application to large or small workloads.
Resumo:
When two stimuli are presented simultaneously to an observer, the perceived temporal order does not always correspond to the actual one. In three experiments we examined how the location and spatial predictability of visual stimuli modulate the perception of temporal order. Thirty-two participants had to report the temporal order of appearance of two visual stimuli. In Experiment 1, both stimuli were presented at the same eccentricity and no perceptual asynchrony between them was found. In Experiment 2, one stimulus was presented close to the fixation point and the other, peripheral, stimulus was presented in separate blocks in two eccentricities (4.8º and 9.6º). We found that the peripheral stimulus was perceived to be delayed in relation to the central one, with no significant difference between the delays obtained in the two eccentricities. In Experiment 3, using three eccentricities (2.5º, 7.3º and 12.1º) for the presentation of the peripheral stimulus, we compared a condition in which its location was highly predictable with two other conditions in which its location was progressively less predictable. Here, the perception of the peripheral stimulus was also delayed in relation to the central one, with this delay depending on both the eccentricity and predictability of the stimulus. We argue that attentional deployment, manipulated by the spatial predictability of the stimulus, seems to play an important role in the temporal order perception of visual stimuli. Yet, under whichever condition of spatial predictability, basic sensory and attentional processes are unavoidably entangled and both factors must concur to the perception of temporal order.
Resumo:
In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia) and higher order aberrations (coma, spherical aberration, etc.). We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45º and 90º. We used a device known as the Hartmann-Shack (HS) sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE) of less than 0.1 µm for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5º for the axis. This precision is sufficient for customized corneal ablations, among other applications.
Resumo:
The influence of aging on memory has been extensively studied, but the importance of short-term memory and recall sequence has not. The objective of the current study was to examine the recall order of words presented on lists and to determine if age affects recall sequence. Physically and psychologically healthy male subjects were divided into two groups according to age, i.e., 23 young subjects (20 to 30 years) and 50 elderly subjects (60 to 70 years) submitted to the Wechsler Adult Intelligence Scale-Revised and the free word recall test. The order of word presentation significantly affected the 3rd and 4th words recalled (P < 0.01; F = 14.6). In addition, there was interaction between the presentation order and the type of list presented (P < 0.05; F = 9.7). Also, both groups recalled the last words presented from each list (words 13-15) significantly more times 3rd and 4th than words presented in all remaining positions (P < 0.01). The order of word presentation also significantly affected the 5th and 6th words recalled (P = 0.05; F = 7.5) and there was a significant interaction between the order of presentation and the type of list presented (P < 0.01; F = 20.8). The more developed the cognitive functions, resulting mainly from formal education, the greater the cognitive reserve, helping to minimize the effects of aging on the long-term memory (episodic declarative).
Resumo:
The objective of this study was to investigate the phenomenon of learning generalization of a specific skill of auditory temporal processing (temporal order detection) in children with dyslexia. The frequency order discrimination task was applied to children with dyslexia and its effect after training was analyzed in the same trained task and in a different task (duration order discrimination) involving the temporal order discrimination too. During study 1, one group of subjects with dyslexia (N = 12; mean age = 10.9 ± 1.4 years) was trained and compared to a group of untrained dyslexic children (N = 28; mean age = 10.4 ± 2.1 years). In study 2, the performance of a trained dyslexic group (N = 18; mean age = 10.1 ± 2.1 years) was compared at three different times: 2 months before training, at the beginning of training, and at the end of training. Training was carried out for 2 months using a computer program responsible for training frequency ordering skill. In study 1, the trained group showed significant improvement after training only for frequency ordering task compared to the untrained group (P < 0.001). In study 2, the children showed improvement in the last interval in both frequency ordering (P < 0.001) and duration ordering (P = 0.01) tasks. These results showed differences regarding the presence of learning generalization of temporal order detection, since there was generalization of learning in only one of the studies. The presence of methodological differences between the studies, as well as the relationship between trained task and evaluated tasks, are discussed.
Resumo:
The application of continuous positive airway pressure (CPAP) produces important hemodynamic alterations, which can influence breathing pattern (BP) and heart rate variability (HRV). The aim of this study was to evaluate the effects of different levels of CPAP on postoperative BP and HRV after coronary artery bypass grafting (CABG) surgery and the impact of CABG surgery on these variables. Eighteen patients undergoing CABG were evaluated postoperatively during spontaneous breathing (SB) and application of four levels of CPAP applied in random order: sham (3 cmH2O), 5 cmH2O, 8 cmH2O, and 12 cmH2O. HRV was analyzed in time and frequency domains and by nonlinear methods and BP was analyzed in different variables (breathing frequency, inspiratory tidal volume, inspiratory and expiratory time, total breath time, fractional inspiratory time, percent rib cage inspiratory contribution to tidal volume, phase relation during inspiration, phase relation during expiration). There was significant postoperative impairment in HRV and BP after CABG surgery compared to the preoperative period and improvement of DFAα1, DFAα2 and SD2 indexes, and ventilatory variables during postoperative CPAP application, with a greater effect when 8 and 12 cmH2O were applied. A positive correlation (P < 0.05 and r = 0.64; Spearman) was found between DFAα1 and inspiratory time to the delta of 12 cmH2O and SB of HRV and respiratory values. Acute application of CPAP was able to alter cardiac autonomic nervous system control and BP of patients undergoing CABG surgery and 8 and 12 cmH2O of CPAP provided the best performance of pulmonary and cardiac autonomic functions.
Resumo:
The increasing consumption of soybeans due to its bioactive compounds has attracted interest in describing the grain's constituents and variation during processing. Phytate has been the aim of much research since it chelates essential minerals but also has beneficial antioxidant effects. This study evaluated the variation of phytate, calcium, zinc, and iron during soaking and cooking of soybeans. The phytate: Zn and phytate: Fe molar ratios were determined in order to estimate the bioavailability of these minerals. Six food-type varieties were used: BR 36, BRS 213, BRS 216, BRS 232, BRS 155, and Embrapa 48. The samples were soaked in water 3:1 (w/w) for 12 hours at room temperature and cooked. Cooking time was determined by modeling the softening of each variety using fractional conversion. Water content, phytate, and minerals were determined in raw, soaked and cooked samples. The water content of raw grains for all varieties was 9.9 g.100 g-1 increasing to a range of 58.1-63.7 g.100 g-1 after soaking and 63.1-66.0 g.100 g-1 after cooking. Soaking caused a significant reduction in phytate (23-30%), but cooking caused no additional reduction. The phytate: Zn molar ratio was 20 indicating that zinc absorption could be impaired, while the phytate: Fe molar ratio was 8, below the level of compromising absorption