24 resultados para Mind the gap
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)
Resumo:
Consumers worldwide are increasingly concerned with sustainable production and consumption. Recently, a comprehensive study ranked 17 countries in regard to their environmentally friendly behaviour among consumers. Brazil was one of the top countries in the list. Yet, several studies highlight significant differences between consumers` intentions to consume ethically, and their actual purchase behaviour: the so-called `Attitude-Behaviour Gap`. In developing countries, few studies have been conducted on this issue. The objective of this study is therefore to investigate the gap between citizens` sustainability-related attitudes and food purchasing behaviour using empirical data from Brazil. To this end, Brazilian citizens` attitudes towards pig production systems were mapped through conjoint analysis and their coexistence with relevant pork product-related purchasing behaviour of consumers was investigated through cluster analysis. The conjoint experiment was carried Out with empirical data collected from 475 respondents surveyed in the South and Center-West regions of Brazil. The results of the conjoint analysis were used for a subsequent cluster analysis in order to identify clusters of Brazilian citizens with diversified attitudes towards pig production systems, using socio-demographics, attitudes towards sustainability-related themes that are expected to influence the way they evaluate pig production systems, and consumption frequency of various pork products as clusters` background information. Three clusters were identified as `indifferent`, `environmental conscious` and `sustainability-oriented` citizens. Although attitudes towards environment and nature had indeed an influence on citizens` specific attitudes towards pig farming at the cluster level, the relationship between `citizenship` and consumption behaviour was found to be weak. This finding is similar to previous research conducted with European consumers: what people (in their role of citizens) think about pig production systems does not appear to significantly influence their pork consumption choices. Improvements in the integrated management of this chain would better meet consumers` sustainability-related expectations towards pig production systems.
Resumo:
In this work we report on a comparison of some theoretical models usually used to fit the dependence on temperature of the fundamental energy gap of semiconductor materials. We used in our investigations the theoretical models of Viña, Pässler-p and Pässler-ρ to fit several sets of experimental data, available in the literature for the energy gap of GaAs in the temperature range from 12 to 974 K. Performing several fittings for different values of the upper limit of the analyzed temperature range (Tmax), we were able to follow in a systematic way the evolution of the fitting parameters up to the limit of high temperatures and make a comparison between the zero-point values obtained from the different models by extrapolating the linear dependence of the gaps at high T to T = 0 K and that determined by the dependence of the gap on isotope mass. Using experimental data measured by absorption spectroscopy, we observed the non-linear behavior of Eg(T) of GaAs for T > ΘD.
Resumo:
Objective To assess trends in the prevalence and social distribution of child stunting in Brazil to evaluate the effect of income and basic service redistribution policies implemented in that country in the recent past. Methods The prevalence of stunting (height-for-age z score below \22122 using the Child Growth Standards of the World Health Organization) among children aged less than 5 years was estimated from data collected during national household surveys carried out in Brazil in 1974\201375 (n = 34 409), 1989 (n = 7374), 1996 (n = 4149) and 2006\201307 (n = 4414). Absolute and relative socioeconomic inequality in stunting was measured by means of the slope index and the concentration index of inequality, respectively. Findings Over a 33-year period, we documented a steady decline in the national prevalence of stunting from 37.1 per cent to 7.1 per cent. Prevalence dropped from 59.0 per cent to 11.2 per cent in the poorest quintile and from 12.1 per cent to 3.3 per cent among the wealthiest quintile. The decline was particularly steep in the last 10 years of the period (1996 to 2007), when the gaps between poor and wealthy families with children under 5 were also reduced in terms of purchasing power; access to education, health care and water and sanitation services; and reproductive health indicators.Conclusion In Brazil, socioeconomic development coupled with equity-oriented public policies have been accompanied by marked improvements in living conditions and a substantial decline in child undernutrition, as well as a reduction of the gap in nutritional status between children in the highest and lowest socioeconomic quintiles. Future studies will show whether these gains will be maintained under the current global economic crisis
Resumo:
Using the solutions of the gap equations of the magnetic-color-flavor-locked (MCFL) phase of paired quark matter in a magnetic field, and taking into consideration the separation between the longitudinal and transverse pressures due to the field-induced breaking of the spatial rotational symmetry, the equation of state of the MCFL phase is self-consistently determined. This result is then used to investigate the possibility of absolute stability, which turns out to require a field-dependent ""bag constant"" to hold. That is, only if the bag constant varies with the magnetic field, there exists a window in the magnetic field vs bag constant plane for absolute stability of strange matter. Implications for stellar models of magnetized (self-bound) strange stars and hybrid (MCFL core) stars are calculated and discussed.
Resumo:
The Amazon Basin provides an excellent environment for studying the sources, transformations, and properties of natural aerosol particles and the resulting links between biological processes and climate. With this framework in mind, the Amazonian Aerosol Characterization Experiment (AMAZE-08), carried out from 7 February to 14 March 2008 during the wet season in the central Amazon Basin, sought to understand the formation, transformations, and cloud-forming properties of fine-and coarse-mode biogenic aerosol particles, especially as related to their effects on cloud activation and regional climate. Special foci included (1) the production mechanisms of secondary organic components at a pristine continental site, including the factors regulating their temporal variability, and (2) predicting and understanding the cloud-forming properties of biogenic particles at such a site. In this overview paper, the field site and the instrumentation employed during the campaign are introduced. Observations and findings are reported, including the large-scale context for the campaign, especially as provided by satellite observations. New findings presented include: (i) a particle number-diameter distribution from 10 nm to 10 mu m that is representative of the pristine tropical rain forest and recommended for model use; (ii) the absence of substantial quantities of primary biological particles in the submicron mode as evidenced by mass spectral characterization; (iii) the large-scale production of secondary organic material; (iv) insights into the chemical and physical properties of the particles as revealed by thermodenuder-induced changes in the particle number-diameter distributions and mass spectra; and (v) comparisons of ground-based predictions and satellite-based observations of hydrometeor phase in clouds. A main finding of AMAZE-08 is the dominance of secondary organic material as particle components. The results presented here provide mechanistic insight and quantitative parameters that can serve to increase the accuracy of models of the formation, transformations, and cloud-forming properties of biogenic natural aerosol particles, especially as related to their effects on cloud activation and regional climate.
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Aims Following sinoaortic denervation (SAD), isolated rat aortas present oscillatory contractions and demonstrate a heightened contraction for alpha-adrenergic agonists. Our aim was to verify the effects of SAD on connexin43 (Cx43) expression and phenylephrine-induced contraction in isolated aortas. Methods and results Three days after surgery (SAD or sham operation), isolated aortic rings were exposed to phenylephrine and acetylcholine (0.1-10 mu M) in the presence or absence of the gap junction blocker 18 beta-glycyrrhetinic acid (18 beta-GA, 100 mu M). Vascular reactivity to potassium chloride (KCl, 4.7-120 mM) was also examined. The incidence of rats presenting oscillatory contractions was measured. Effects of SAD on the vascular smooth muscle expression of the Cx43 mRNA by RT-PCR and western blotting for Cx43 protein were examined. Phenylephrine-induced contraction was higher in SAD rat aortas compared with the control. In the presence of 18 beta-GA, the response to phenylephrine was similar in both groups. Oscillatory contractions were observed in 10/10 SAD rat aortas vs. 2/10 controls. Relaxing response to acetylcholine was similar in both groups, but in the presence of 18 beta-GA, the response to acetylcholine decreased significantly in the sham-operated group (82.7 +/- 7.6% reduction of relaxation), whereas a half-maximal relaxation (reduction of 46.2 +/- 5.3%) took place in SAD rat aortas. KCl-induced contraction was similar in both groups. Following SAD, RT-PCR revealed significantly increased levels of Cx43 mRNA (9.85 fold, P < 0.01). Western blot analysis revealed greater levels of Cx43 protein (P < 0.05). Conclusion Blood pressure variability evoked by SAD leads to increased expression of Cx43, which could contribute to enhanced phenylephrine-induced contraction and oscillatory activity in isolated aortas.
Resumo:
RESUMO: Analisamos neste artigo a teoria do conhecimento de Arthur Schopenhauer com base em sua dissertação Sobre a quádrupla raiz do princípio de razão suficiente (1813), seu ensaio Sobre a visão e as cores (1816), os dois primeiros livros de O mundo como vontade e representação (1819), bem como o apêndice a esta obra intitulado Crítica da filosofia kantiana. Aqui temos em mente a relação de Schopenhauer com as filosofias anteriores (em especial a de Kant) e a fundamentação de sua intuição do mundo como Vontade baseada em uma epistemologia de raízes kantianas.
Resumo:
Aims. To investigate the effects of using bromazepam on the relative power in alpha while performing a typing task. Bearing in mind the particularities of each brain hemisphere, our hypothesis was that measuring the relative power would allow its to investigate the effects of bromazepam oil specific areas of the cortex. More, specifically, we expected to observe different patterns of powers in sensory-motor integration, attention and activation processes. Subjects and methods. The sample was made up of 39 subjects (15 males and 24 females) with a mean age of 30 +/- 10 years. The control (placebo) and experimental (3 mg and 6 mg of bromazepam) groups were trained ill the typing task with a randomised double-blind model. Results. A three-way ANOVA and Scheffe test were used to analyse interactions between the factors condition and moment, and between condition and sector Conclusions. The doses used ill this study facilitated motor performance of the typing task. Ill this study, the use of the drug did not prevent learning of the task, but it did appear to concentrate mental effort on more restricted and specific aspects of typing. It also seemed to influence the rhythm and effectiveness of the operations performed during mechanisms related to the encoding and storage often, information. Likewise, a predominance of activity was observed in the left (dominant) frontal area in the 3 mg bromazepam group, which indicates that this close of the drug affords the subject a greater degree of directionality of cortical activity for planning and performing the task. [REV NEUROL 2009; 49: 295-9]
Resumo:
Objectives/Hypothesis: Polysomnography (PSG) is the gold-standard method for diagnosing obstructive sleep apnea (OSA). However, the gap between demand and capacity in performing PSG is a major health-care problem. We sought to validate a short day-time induced sleep for the diagnosis of OSA. Study Design: Prospective diagnostic method validation. Methods: We studied 25 consecutive patients referred to the sleep laboratory and 15 healthy volunteers. All subjects were evaluated by means of full overnight PSG (Full-PSG) and short day-time induced-sleep PSG (Induced-PSG). Sleep was monitored during both procedures (Embla, 16 channels). Sleep was induced by slow intravenous drip infusion of midazolam. Results: The population studied (N = 40) was 60% male (mean age, 42 +/- 10 years; body mass index, 29 +/- 6.5 kg/m(2)). Sleep was successfully induced in all subjects, and no complications were observed (midazolam doses, 6.2 +/- 3.8 mg; time of induced sleep 41.5 +/- 18.9 minutes). The apnea-hypopnea index (AHI) and minimal oxygen saturation during Full-PSG versus Induced-PSG were similar: median AHI (with 25%-75% interquartile range) was 13 (3-35) events per hour versus 17 (4-36) events per hour, and median oxygen saturation was 84% (75-90) versus 85% (76-92); P = .89 and P = .53, respectively. The majority of the respiratory events during induced sleep were obstructive and similar to those observed during Full-PSG. AHI and lowest oxygen saturation during Induced-PSG correlated significantly with Full-PSG (r = 0.67 and r = 0.77, respectively). Sensitivity and specificity for the diagnosis of OSA (AHI > 15 events per hour) by Induced-PSG were 0.83 and 0.72, respectively. Conclusions: Induced-PSG by midazolam during the day is safe and correlates with Full-PSG; it therefore is a promising alternative method in the diagnosis of OSA.
Resumo:
Objective To assess trends in the prevalence and social distribution of child stunting in Brazil to evaluate the effect of income and basic service redistribution policies implemented in that country in the recent past. Methods The prevalence of stunting (height-for-age z score below 2 using the Child Growth Standards of the World Health Organization) among children aged less than 5 years was estimated from data collected during national household surveys carried out in Brazil in 1974-75 (n = 34 409), 1989 (n = 7374), 1996 (n = 4149) and 2006-07 (n = 4414). Absolute and relative socioeconomic inequality in stunting was measured by means of the slope index and the concentration index of inequality, respectively. Findings Over a 33-year period, we documented a steady decline in the national prevalence of stunting from 37.1% to 7.1%. Prevalence dropped from 59.0% to 11.2% in the poorest quintile and from 12.1% to 3.3% among the wealthiest quintile. The decline was particularly steep in the last 10 years of the period (1996 to 2007), when the gaps between poor and wealthy families with children under 5 were also reduced in terms of purchasing power; access to education, health care and water and sanitation services; and reproductive health indicators. Conclusion In Brazil, socioeconomic development coupled with equity-oriented public policies have been accompanied by marked improvements in living conditions and a substantial decline in child undernutrition, as well as a reduction of the gap in nutritional status between children in the highest and lowest socioeconomic quintiles. Future studies will show whether these gains will be maintained under the current global economic crisis.
Resumo:
The CoRoT space observatory is a project which is led by the French space agency CNES and leading space research institutes in Austria, Brazil, Belgium, Germany and Spain and also the European Space Agency ESA. CoRoT observed since its launch in December 27, 2006 about 100 000 stars for the exoplanet channel, during 150 days uninterrupted high-precision photometry. Since the The CoRoT-team has several exoplanet candidates which are currently analyzed under its study, we report here the discoveries of nine exoplanets which were observed by CoRoT. Discovered exoplanets such as CoRoT-3b populate the brown dwarf desert and close the gap of measured physical properties between usual gas giants and very low mass stars. CoRoT discoveries extended the known range of planet masses down to about 4.8 Earth-masses (CoRoT-7b) and up to 21 Jupiter masses (CoRoT-3b), the radii to about 1.68 x 0.09 R (Earth) (CoRoT-7b) and up to the most inflated hot Jupiter with 1.49 x 0.09 R (Earth) found so far (CoRoT-1b), and the transiting exoplanet with the longest period of 95.274 days (CoRoT-9b). Giant exoplanets have been detected at low metallicity, rapidly rotating and active, spotted stars. Two CoRoT planets have host stars with the lowest content of heavy elements known to show a transit hinting towards a different planethost-star-metallicity relation then the one found by radial-velocity search programs. Finally the properties of the CoRoT-7b prove that rocky planets with a density close to Earth exist outside the Solar System. Finally the detection of the secondary transit of CoRoT-1b at a sensitivity level of 10(-5) and the very clear detection of the ""super-Earth"" CoRoT-7b at 3.5 x 10(-4) relative flux are promising evidence that the space observatory is being able to detect even smaller exoplanets with the size of the Earth.
Resumo:
Synaptic modulation by activity-dependent changes constitutes a cellular mechanism for neuronal plasticity. However, it is not clear how the complete lack of neuronal signaling specifically affects elements involved in the communication between neurons. In the retina, it is now well established that both chemical and electrical synapses are essential to mediate the transmission of visual signaling triggered by the photoreceptors. In this study, we compared the expression of synaptic proteins in the retinas of wild-type (WT) vs. rd/rd mice, an animal model that displays inherited and specific ablation of photoreceptors caused by a mutation in the gene encoding the beta-subunit of rod cGMP-phosphodiesterase (Pde6b(rd1)). We specifically examined the expression of connexins (Cx), the proteins that form the gap junction channels of electrical synapses, in addition to synaptophysin and synapsin 1, which are involved in the release of neurotransmitters at chemical synapses. Our results revealed that Cx36 gene expression levels are lower in the retinas of rd/rd when compared with WT. Confocal analysis indicated that Cx36 immunolabeling almost disappeared in the outer plexiform layer without significant changes in protein distribution within the inner plexiform layer of rd/rd retinas. Likewise, synaptophysin expression remarkably decreased in the outer plexiform layer of rd/rd retinas, and this down-regulation was also associated with diminished transcript levels. Furthermore, we observed down-regulation of Cx57 gene expression in rd/rd retinas when compared with WT and also changes in protein distribution. Interestingly, Cx45 and synapsin I expression in rd/rd retinas showed no noticeable changes when compared with WT. Taken together, our results revealed that the loss of photoreceptors leads to decreased expression of some synaptic proteins. More importantly, this study provides evidence that neuronal activity regulates, but is not essential to maintain, the expression of synaptic elements. (c) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.
Resumo:
The one-fluid magnetohydrodynamic (MHD) theory of magnetorotational instability (MRI) in an ideal plasma is presented. The theory predicts the possibility of MRI for arbitrary 0, where 0 is the ratio of the plasma pressure to the magnetic field pressure. The kinetic theory of MRI in a collisionless plasma is developed. It is demonstrated that as in the ideal MHD, MRI can occur in such a plasma for arbitrary P. The mechanism of MRI is discussed; it is shown that the instability appears because of a perturbed parallel electric field. The electrodynamic description of MRI is formulated under the assumption that the dispersion relation is expressed in terms of the permittivity tensor; general properties of this tensor are analyzed. It is shown to be separated into the nonrotational and rotational parts. With this in mind, the first step for incorporation of MRI into the general theory of plasma instabilities is taken. The rotation effects on Alfven waves are considered.
Resumo:
In this paper, a detailed study of the capacitance spectra obtained from Au/doped-polyaniline/Al structures in the frequency domain (0.05 Hz-10 MHz), and at different temperatures (150-340 K) is carried out. The capacitance spectra behavior in semiconductors can be appropriately described by using abrupt cut-off models, since they assume that the electronic gap states that can follow the ac modulation have response times varying rapidly with a certain abscissa, which is dependent on both temperature and frequency. Two models based on the abrupt cut-off concept, formerly developed to describe inorganic semiconductor devices, have been used to analyze the capacitance spectra of devices based on doped polyaniline (PANI), which is a well-known polymeric semiconductor with innumerous potential technological applications. The application of these models allowed the determination of significant parameters, such as Debye length (approximate to 20 nm), position of bulk Fermi level (approximate to 320 meV) and associated density of states (approximate to 2x10(18) eV(-1) cm(-3)), width of the space charge region (approximate to 70 nm), built-in potential (approximate to 780 meV), and the gap states` distribution.
Resumo:
We discuss the generalized eigenvalue problem for computing energies and matrix elements in lattice gauge theory, including effective theories such as HQET. It is analyzed how the extracted effective energies and matrix elements converge when the time separations are made large. This suggests a particularly efficient application of the method for which we can prove that corrections vanish asymptotically as exp(-(E(N+1) - E(n))t). The gap E(N+1) - E(n) can be made large by increasing the number N of interpolating fields in the correlation matrix. We also show how excited state matrix elements can be extracted such that contaminations from all other states disappear exponentially in time. As a demonstration we present numerical results for the extraction of ground state and excited B-meson masses and decay constants in static approximation and to order 1/m(b) in HQET.