31 resultados para Fibonacci series and golden ratio

em Universidade Federal do Rio Grande do Norte(UFRN)


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This thesis aims to present a study of the Fibonacci sequence, initiated from a simple problem of rabbits breeding and the Golden Ratio, which originated from a geometrical construction, for applications in basic education. The main idea of the thesis is to present historical records of the occurrence of these concepts in nature and science and their influence on social, cultural and scientific environments. Also, it will be presented the identification and the characterization of the basic properties of these concepts and howthe connection between them occurs,and mainly, their intriguing consequences. It is also shown some activities emphasizing geometric constructions, links to other mathematics areas, curiosities related to these concepts and the analysis of questions present in vestibular (SAT-Scholastic Aptitude Test) and Enem(national high school Exam) in order to show the importance of these themes in basic education, constituting an excellent opportunity to awaken the students to new points of view in the field of science and life, from the presented subject and to promote new ways of thinking mathematics as a transformative science of society.

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In this paper we investigate the spectra of band structures and transmittance in magnonic quasicrystals that exhibit the so-called deterministic disorders, specifically, magnetic multilayer systems, which are built obeying to the generalized Fibonacci (only golden mean (GM), silver mean (SM), bronze mean (BM), copper mean (CM) and nickel mean (NM) cases) and k-component Fibonacci substitutional sequences. The theoretical model is based on the Heisenberg Hamiltonian in the exchange regime, together with the powerful transfer matrix method, and taking into account the RPA approximation. The magnetic materials considered are simple cubic ferromagnets. Our main interest in this study is to investigate the effects of quasiperiodicity on the physical properties of the systems mentioned by analyzing the behavior of spin wave propagation through the dispersion and transmission spectra of these structures. Among of these results we detach: (i) the fragmentation of the bulk bands, which in the limit of high generations, become a Cantor set, and the presence of the mig-gap frequency in the spin waves transmission, for generalized Fibonacci sequence, and (ii) the strong dependence of the magnonic band gap with respect to the parameters k, which determines the amount of different magnetic materials are present in quasicrystal, and n, which is the generation number of the sequence k-component Fibonacci. In this last case, we have verified that the system presents a magnonic band gap, whose width and frequency region can be controlled by varying k and n. In the exchange regime, the spin waves propagate with frequency of the order of a few tens of terahertz (THz). Therefore, from a experimental and technological point of view, the magnonic quasicrystals can be used as carriers or processors of informations, and the magnon (the quantum spin wave) is responsible for this transport and processing

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Objetivo: relatar a evolução de uma série de casos de gestação em mulheres previamente submetidas à cirurgia de bypass gástrico para tratamento de obesidade grave. Métodos: cinco casos consecutivos de gravidez após gastroplastia ocorridos entre 2001 e 2004 foram avaliados. As pacientes tinham idade entre 30 e 34 anos e todas haviam sido submetidas à cirurgia de Capella. Aspectos clínicos, laboratoriais e do acompanhamento materno e fetal foram considerados, durante o período gestacional e após o parto. Foi realizada revisão da literatura internacional, por meio das bases de dados MEDLINE e Web of Science, utilizando os seguintes unitermos: gastroplasty, gastric bypass surgery, bariatric surgery e pregnancy. Resultados: todas as gestações observadas foram únicas e não ocorreram complicações obstétricas, durante o seguimento pré-natal e parto. Também não houve registro de recém-nascidos prematuros ou de baixo peso ao nascimento. Conclusão: nossos dados sugerem que a gravidez após gastroplastia é segura para a mãe e feto. Entretanto, em virtude do limitado volume de informação disponível sobre o tema, investigações adicionais são necessárias para estabelecer recomendações apropriadas com relação ao seguimento dessas gestações _________________________________________________ABSTRACT Purpose: we report a small series of pregnant women who underwent gastric bypass surgery for severe obesity, with a review of the literature on this topic. Methods: five consecutive cases of pregnancy after gastroplasty between 2001 and 2004 were evaluated, and clinical, laboratory and therapeutic features were considered. Patients were 30 to 34 years old and all had been submitted to gastroplasty by the Capella technique. The outcomes for both the pregnant woman and the fetus were evaluated. A search of the English language literature was done through MEDLINE and Web of Science databases with the following terms: gastroplasty, gastric bypass surgery, bariatric surgery, and pregnancy. Results: all 5 pregnancies were singleton. No major obstetric complications were observed and there were no premature or lowbirth weight infants. Conclusion: our data suggest that pregnancy following gastroplasty is safe for mother and fetus. However, since information about this topic is limited, further investigations are required to establish appropriate recommendations concerning the follow-up of these pregnancies

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relatar a evolução de uma série de casos de gestação em mulheres previamente submetidas à cirurgia de bypass gástrico para tratamento de obesidade grave. Métodos: cinco casos consecutivos de gravidez após gastroplastia ocorridos entre 2001 e 2004 foram avaliados. As pacientes tinham idade entre 30 e 34 anos e todas haviam sido submetidas à cirurgia de Capella. Aspectos clínicos, laboratoriais e do acompanhamento materno e fetal foram considerados, durante o período gestacional e após o parto. Foi realizada revisão da literatura internacional, por meio das bases de dados MEDLINE e Web of Science, utilizando os seguintes unitermos: gastroplasty, gastric bypass surgery, bariatric surgery e pregnancy. Resultados: todas as gestações observadas foram únicas e não ocorreram complicações obstétricas, durante o seguimento pré-natal e parto. Também não houve registro de recém-nascidos prematuros ou de baixo peso ao nascimento. Conclusão: nossos dados sugerem que a gravidez após gastroplastia é segura para a mãe e feto. Entretanto, em virtude do limitado volume de informação disponível sobre o tema, investigações adicionais são necessárias para estabelecer recomendações apropriadas com relação ao seguimento dessas gestações

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The financial crisis that occurred between the years 2007 and 2008, known as the subprime crisis, has highlighted the governance of companies in Brazil and worldwide. To monitor the financial risk, quantitative tools of risk management were created in the 1990s, after several financial disasters. The market turmoil has also led companies to invest in the development and use of information, which are applied as tools to support process control and decision making. Numerous empirical studies on informational efficiency of the market have been made inside and outside Brazil, revealing whether the prices reflect the information available instantly. The creation of different levels of corporate governance on BOVESPA, in 2000, made the firms had greater impairment in relation to its shareholders with greater transparency in their information. The purpose of this study is to analyze how the subprime financial crisis has affected, between January 2007 and December 2009, the volatility of stock returns in the BM&BOVESPA of companies with greater liquidity at different levels of corporate governance. From studies of time series and through the studies of events, econometric tests were performed by the EVIEWS, and through the results obtained it became evident that the adoption of good practices of corporate governance affect the volatility of returns of companies

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Post-menarche patients with clinical signs of vulvovaginitis were analyzed in this study, whose aims were the following: identify the frequency of C. albicans and non C. albicans species and negative results, correlate the vaginal culture for yeast with risk factors and symptomatology; compare positive and negative results for yeast in the vaginal and anal cultures; compare the positive results for C. albicans with other results found in the vaginal and anal cultures; and compare concomitant positivity for C. albicans and non C. albicans in the vaginal and anal cultures. Sample selection occurred between May, 2003 and May, 2005, and included 99 patients from Natal, Brazil. The laboratory methods used consisted of CHROMagar Candida culture medium, thermotolerance test at 42-45°C and hypertonic NaCL, in addition to the classic methods of carbohydrate assimilation and fermentation. We used absolute numbers, percentages, means of central tendency, chi-squared test (χ2) with Yates correction, Fisher s exact test and odds ratio for statistical analysis. The most frequent species was C. albicans in 69% of the cases. The positivity for Candida spp showed an association with the use of tight-fitting intimate clothing and/or synthetics, allergic diseases and the occurrence of itching, leukorrhea and erythema. Anal colonization increased the likelihood of vaginal contamination by 2.8 and 4.9 times, respectively, for Candida spp and C. albicans. When compared to the other species, C. albicans-positive anal colonization increased by 3.7 times the likelihood of vaginal positivity. These data suggest likely vaginal contamination originating in the anus

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Compounded medicines have been reported by the ANVISA due to decreased of the therapeutic response or toxicity of these formulations. The aim of this work was to investigate the physicochemical quality control among naproxen sodium oral suspensions 25 mg/mL obtained from six compounding pharmacies (A, B, C, D, E and F) and the manufactured suspension (R). In the quality control test, the tests of pH, content, homogeneity, volume and physical and organoleptic characteristics were performed according to the Brazilian Pharmacopoeia. The analytical method for determination of naproxen in suspensions was validate. This method showed excellent precision, accuracy, linearity and specificity. In the content test the suspensions B, C and E showed lower value and the F suspension showed a high value of the content. The products C and E were disapproved in the description of the physical and organoleptic characteristics test. In the pH test, three suspensions were outside specifications (C, E and F). Only the products R, A and D showed satisfactory results in these tests and therefore they were approved for relative bioavailability test. The R, A and D suspensions were orally administered to Wistar rats and the blood samples were taken at time intervals of 10, 20, 40, 60 min, 3, 4, 6, 24 and 48 h. The plasma samples were immediately stored at 80 ºC until analysis of HPLC. The bioanalytical method validation showed specificity, linearity (R2 0.9987), precision, accuracy, good recovery and stability. The chromatographic conditions were: flow rate of 1.2 mL.min-1 with a mobile phase of acetonitrile : sodium phosphate buffer pH 4.0 (50:50, v/v) at 280 nm, using a C18 column. The confidence interval of 90% for the Cmax and AUCt ratio was within the range of 80 - 125% proposed by the FDA. Only one suspension, obtained from the compounding pharmacy D, was considered bioequivalent to the rate of absorption under the conditions proposed by this study. Thus, the results indicate the need for strict supervision from the relevant authorities to ensure the patient safety and the quality of compounded drugs by pharmacies

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In this paper artificial neural network (ANN) based on supervised and unsupervised algorithms were investigated for use in the study of rheological parameters of solid pharmaceutical excipients, in order to develop computational tools for manufacturing solid dosage forms. Among four supervised neural networks investigated, the best learning performance was achieved by a feedfoward multilayer perceptron whose architectures was composed by eight neurons in the input layer, sixteen neurons in the hidden layer and one neuron in the output layer. Learning and predictive performance relative to repose angle was poor while to Carr index and Hausner ratio (CI and HR, respectively) showed very good fitting capacity and learning, therefore HR and CI were considered suitable descriptors for the next stage of development of supervised ANNs. Clustering capacity was evaluated for five unsupervised strategies. Network based on purely unsupervised competitive strategies, classic "Winner-Take-All", "Frequency-Sensitive Competitive Learning" and "Rival-Penalize Competitive Learning" (WTA, FSCL and RPCL, respectively) were able to perform clustering from database, however this classification was very poor, showing severe classification errors by grouping data with conflicting properties into the same cluster or even the same neuron. On the other hand it could not be established what was the criteria adopted by the neural network for those clustering. Self-Organizing Maps (SOM) and Neural Gas (NG) networks showed better clustering capacity. Both have recognized the two major groupings of data corresponding to lactose (LAC) and cellulose (CEL). However, SOM showed some errors in classify data from minority excipients, magnesium stearate (EMG) , talc (TLC) and attapulgite (ATP). NG network in turn performed a very consistent classification of data and solve the misclassification of SOM, being the most appropriate network for classifying data of the study. The use of NG network in pharmaceutical technology was still unpublished. NG therefore has great potential for use in the development of software for use in automated classification systems of pharmaceutical powders and as a new tool for mining and clustering data in drug development

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Dormancy is an inherent property of the seeds that define the environmental conditions in which they are able to germinate and their presence is an adaptive trait common in species inhabiting semiarid regions. Moreover, the ability of seedling establishment in these environments has been related to the size, strength and chemical characteristics of the seeds. This study investigated patterns of dormancy and germination speed in tree species of the Caatinga, exploring how the seed size influence the processes of germination, seedling size and biomass allocation. In addition, we aim to investigate the chemical characteristics of the reserves, to verify a possible relationship between nutritional content and the process of seed germination. Therefore, seeds were collected from ten species of woody Caatinga for tests of breaking dormancy, germination and biochemical characterization. Overall, the results show that the scarification treatments mechanical and chemical, and thermal shock influenced the percentage and speed of germination in 50 % of the species, suggesting that they have some level of physical dormancy in the seeds. Biochemical characterization showed the existence of large amounts of carbohydrates in the seeds of all species, low proportion of protein and low amounts of neutral lipids. Using linear regression, we demonstrated the existence of a significant relationship between seed size and the ratio of root/shoot where the largest seeds invested a greater amount of resources for shoot growth. The relationship between germination speed and non-reducing sugar content was also significant, so these compounds is related to the maintenance of physiological seed quality. These results confirm some relationships discussed in the literature for cultivated species, but can be applied to the species native to the Caatinga

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The aim of this thesis is to evaluate the quality of public spending on education for the municipalities of the Metropolitan Region of Natal (RMN) in 2009 by use of two theories: The Theory of Welfare (Welfare State) and the Public Choice Theory (TEP), both important to understand the relationship between education and economics. The study also uses principles of microeconomics and public sector economics to get a better idea of the role of education in economy and society. It describes the development of the educational policy in Brazil from 1988 to the Federal Constitution of 2010, following the major changes in basic education during each government. The characteristics of the RMN municipalities were illustrated with socioeconomic indicators, while educational indicators were used to characterize each municipality regarding education. The model used in this study was developed by Bertê, Brunet and Borges, the data was collected on the back of the School Census 2009 and the Brazil Exam 2009 and it was processed quantitavely in the Information System on Public Budgets in Education (SIOPE) by use of the statistical method called standardized score of the normal cumulative distribution function. The quality of public spending on education is the result of the relation between performance indicator ratio and expense ratio. For the qualitative analysis of results, the criteria of efficiency, efficacy and effectiveness were used. The study found that municipalities with higher expenses showed a worse quality of spending and failed to convert the expenditure incurred into performance, thus confirming ineffectiveness

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Prospective descriptive study with quantitative approach, which aimed to analyze the relationship of the knowledge of Nurses and conduct assistance during the process of transfusion, to patients in the ICU of a university hospital in Natal-RN. The sample consisted of 27 professionals from the nursing staff (5 nurses and 22 nursing technicians), climbing in the ICU during the period of data collection. Data collection was through a questionnaire and structured form of observation, in addition to consulting the diary. The results were organized in SPSS 15.0, tabulated, cathegorized and analyzed by descriptive and inferential statistics. The results show a young population, aged between 21 and 32 years (63.0%), female (85.2%). Among those surveyed were the main type of stock, mostly technical, nursing (ρ= 0006), which have little time to experience - up to 2 years (ρ= 0008), did not know the DRC in 153 (ρ= 0019), held greater number of pipelines care in blood (ρ= 0018), the non-participation in training and feel informed about the process of transfusion, showed no significant differences. As for officials, highlighted only the time to experience more than 2 years, carrying out fewer procedures and feel informed about the blood. As for the pipes during the transfusion process, I found that the majority of pipes observed in both the stock and the staff were inadequate, with predominance in the first, both in the pursuit of conduct regarding the shortfall. The averages of inappropriate conduct, predominantly developed by stock, were higher in all stages for appropriate conduct. Analyzing the knowledge about the disease process, the stock market were those who had lower scores of knowledge in three stages. As the relationship between the pipes care and knowledge, we see that at all stages of the process of transfusion inadequate knowledge of the averages were higher, taking a significant difference in the stages pre-transfusion (ρ= 0012). When analyzing the average of pipes behind, we see that in inappropriate conduct were significantly higher (ρ= 0031), who had searched in inadequate knowledge. As for the frequency of total procedures performed, we found a significant predominance (ρ= 0049) of inappropriate conduct (88.9%) of which 81.5% were developed by professionals who had inadequate knowledge, showing moderate correlation (r = 0,516) and odds ratio of 2,750 times the development of inappropriate conduct in trade with inadequate knowledge. We conclude that the professionals surveyed, especially the technicians of nursing stock, showed serious deficiencies with regard to the development of pipelines and knowledge of the transfusion process, showing the inadequacy to develop this therapy. Facing the foregoing, we accept the alternative hypothesis proposed in the study, because we show that the inadequacy of knowledge about the process of transfusion influence in inappropriate conduct implemented by the nursing staff in ICU.

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The construction industry is responsible for generating a lot of waste because of their activities. Consequently, it is noticeable the occurrence of environmental problems in terms of its disposal in inappropriate places. Faced with this problem, some studies have been conducted with the aim of developing technologies and alternatives for recycling construction and demolition waste (CDW), motivated by the scarcity of natural resources and reduction of environmental problems generated. The research aims to characterize the recycled aggregates derived from construction and demolition waste (CDW) produced in the Greater Natal-RN and analyze the performance of mortar coating produced with recycled aggregates. The study includes the chemical , physical and microstructural characterization of recycled aggregates , as well as conducting microscopic analysis and laboratory tests in the fresh state (consistency index , water retention , bulk density and content of entrained air ) and in the hardened state ( compressive strength , tensile strength in bending , water absorption by immersion and capillary , mass density and void ratio ) for mortars produced from different levels of substitution of aggregates ( 0, 20 %, 40 %, 60 %, 80 % and 100 %). The results were satisfactory, providing mortars produced with recycled aggregates, smaller mass density and dynamic modulus values as well as an increase in the rates of absorption and porosity. The tensile strength in bending and compression for TP1 (1:2:8) trait were lower for mortars produced with recycled aggregates and the best result was 20% for replacement. For the TP2 (1:8) mapping, there was an increase in resistance to traction and compression and the best result was for 100% replacement of natural aggregates by recycled. The experiments led to the conclusion that the technical and economic point of view that the mortars produced with recycled aggregates can be used in construction, only if there is an effective control in production processes of recycled aggregate and at the dosage of mortars

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Some fibrous materials, for having properties such as biocompatibility, strength and flexibility, are of great interest for medical and pharmaceutical applications. Among these materials, the fabric made from polylactic acid (PLA) has received special attention, and beside to present these features, is derived from biological source, antimicrobial and bioabsorbable. One of the limitations of PLA is its low wettability and capillarity. Due to this, it is necessary to perform surface modification of the knitted fabric, increasing its hydrophilicity. This work aims to realize the plasma treatment at low pressure in order to increase the surface energy of the polymer. The work was divided into three steps: i) Influence of the gas ratio (oxygen and nitrogen) in the surface modification of PLA fabric after the plasma treatment, ii) physical characterization and physicochemical surface tissue; iii) Evaluation of the effect from current and gas ratio in the capillary rise of tissues and iv) Study of capillarity in yarns and fabrics. The results showed that better gas ratios were the atmospheres: 100% oxygen; 100% nitrogen and 50% oxygen and 50% nitrogen. The surface characterization showed changes in topography and introduction of polar groups which increased the wettability of the fabric. In another part of this study, it was found that the atmosphere containing only nitrogen gas showed the most capillary rise to a current of 0.15 A. The results in capillary yarns and fabrics showed that the thread reached equilibrium in a time much less than the fabric to an atmosphere of 100% nitrogen and 0.15 A. Current Plasma technology was effective to increase the hydrophilicity of PLA fabric, providing surface characteristics favorable for future application in the biomedical field

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The crude glycerine is a raw material that can be used in a wide variety of products. Even with all the impurities inherent in the process of being obtained, the crude glycerin is already in a marketable product. However, the market is much more favorable to the commercialization of purified glycerine. The glycerin is a byproduct gotten from the process of transesterification of waste oils and fats in the production of biodiesel. More recently, the deployment of the new Federal Law of Brazil, related to the implementation of energy resources, forces, from 2008, the increase of 2% biodiesel in diesel common with prospects for 5% (B5). Therefore, it is indispensable that new routes of purification as well as new markets are developed. The objective of this work was to purify, through ion exchange, the crude glycerin, obtained from the reaction of transesterification of cottonseed oil. The cottonseed oil was characterized as the fatty acid composition and physical-chemical properties. The process of ion exchange was conducted in batch. In this process were used strong cation, low anion resins and a mixed resin used to de-ionize water. The purified glycerin was characterized as the content of metals. Tests were performed with activated charcoal adsorption, and for this, it was made tests of time contact with coal as well as quantity of coal used. The time of activation, the amount of the activation solution, the contact time of the glycerol solution in resins, the amount and type of resin applied were evaluated. Considering the analysis made with activated charcoal, when the glycerin solution was treated using the resins individually it was observed that in the conditions for treatment with 10 g of resin, 5 hours of contact with each resin and 50 mL of glycerin solution, its conductivity decreased to a cationic resin, increased to the anionic resin and had a variable value with respect to resin mixed. In the treatment in series, there was a constant decrease in the conductivity of the solution of glycerin. Considering two types of treatment, in series and individually, the content of glycerol in glycerin pre-purified solution with the different resins varied from 12,46 to 29.51% (diluted solution). In analysis performed without the use of activated charcoal, the behavior of the conductivity of the solution of glycerin were similar to results for treatment with activated charcoal, both in series as individually. The solution of glycerin pre-purified had a glycerol content varying from 8.3 to 25.7% (diluted solution). In relation to pH, it had a behavior in accordance with the expected: acid for the glycerin solution treated with cationic resin, basic when the glycerin solution was treated with the anionic resin and neutral when treated with the mixed resin, independent of the kind of procedure used (with or without coal, resins individually or in series). In relation to the color of the glycerin pre-purified solution, the resin that showed the best result was the anionic (colorless), however this does not mean that the solution is more in pure glycerol. The chromatographic analysis of the solutions obtained after the passage through the resins indicated that the treatment was effective by the presence of only one component (glycerol), not considering the solvent of the analysis

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Actually, surveys have been developed for obtaining new materials and methodologies that aim to minimize environmental problems due to discharges of industrial effluents contaminated with heavy metals. The adsorption has been used as an alternative technology effectively, economically viable and potentially important for the reduction of metals, especially when using natural adsorbents such as certain types of clay. Chitosan, a polymer of natural origin, present in the shells of crustaceans and insects, has also been used for this purpose. Among the clays, vermiculite is distinguished by its good ion exchange capacity and in its expanded form enhances its properties by greatly increasing its specific surface. This study aimed to evaluate the functionality of the hybrid material obtained through the modification of expanded vermiculite with chitosan in the removal of lead ions (II) in aqueous solution. The material was characterized by infrared spectroscopy (IR) in order to evaluate the efficiency of modification of matrix, the vermiculite, the organic material, chitosan. The thermal stability of the material and the ratio clay / polymer was evaluated by thermogravimetry. To evaluate the surface of the material was used in scanning electron microscopy (SEM) and (BET). The BET analysis revealed a significant increase in surface area of vermiculite that after interaction with chitosan, was obtained a value of 21, 6156 m2 / g. Adsorption tests were performed according to the particle size, concentration and time. The results show that the capacity of removal of ions through the vermiculite was on average 88.4% for lead in concentrations ranging from 20-200 mg / L and 64.2% in the concentration range of 1000 mg / L. Regarding the particle size, there was an increase in adsorption with decreasing particle size. In fuction to the time of contact, was observed adsorption equilibrium in 60 minutes with adsorption capacity. The data of the isotherms were fitted to equation Freundlich. The kinetic study of adsorption showed that the pseudo second- order model best describes the adsorption adsorption, having been found following values K2=0,024 g. mg-1 min-1and Qmax=25,75 mg/g, value very close to the calculated Qe = 26.31 mg / g. From the results we can conclude that the material can be used in wastewater treatment systems as a source of metal ions adsorbent due to its high adsorption capacity