Introduction Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decade... more Introduction Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decades, but inflammatory activation in this setting is still unpredictable and is associated with several postoperative complications. Perioperative levels of macrophage migration inhibitory factor (MIF) and other inflammatory mediators could be implicated in adverse outcomes in cardiac surgery. Methods Serum levels of MIF, monocyte chemoattractant protein (MCP)-1, soluble CD40 ligand, IL-6 and IL-10 from 93 patients subjected to CPB were measured by enzyme-linked immunosorbent assay and compared with specific and global postoperative organ dysfunctions through multiple organ dysfunction score (MODS) and sequential organ failure assessment (SOFA). Results Most of the cytokines measured had a peak of production between 3 and 6 hours after CPB, but maximum levels of MIF occurred earlier, at the cessation of CPB. Among specific organ dysfunctions, the most frequent was hematological, occurring in 82% of the patients. Circulatory impairment was observed in 73.1% of the patients, and 51% of these needed inotropics or vasopressors within the first 24 hours after surgery. The third most frequent dysfunction was pulmonary, occurring in 48.4% of the patients. Preoperative levels of MIF showed a relevant direct correlation with the intensity of global organ dysfunction measured by SOFA (ρ = 0.46, p < 0.001) and MODS (ρ = 0.50, p < 0.001) on the third day after surgery. MCP-1 production was associated with postoperative thrombocytopenia, and MIF was related to the use of a high dose of vasopressors in patients with cardiovascular impairment and also to lower values of the ratio of partial arterial oxygen tension (PaO2) to fraction of inspired oxygen (FiO2) registered in the first 24 hours after CPB. Conclusion Despite the multifactorial nature of specific or multiple organ dysfunctions, MIF should be explored as a predicting factor of organ dysfunction, or even as a potential therapeutic target in decreasing postoperative complications.
Page 1. Chapter 11 Recruitment of Dry Forest Tree Species in Central Brazil Pastures Aldicir Scar... more Page 1. Chapter 11 Recruitment of Dry Forest Tree Species in Central Brazil Pastures Aldicir Scariot, Daniel LM Vieira, Alexandre B. Sampaio, Ernestino Guarino and Anderson Sevilha 11.1 Introduction Despite its importance ...
Tropical dry forests are the most threatened tropical terrestrial ecosystem. However, few studies... more Tropical dry forests are the most threatened tropical terrestrial ecosystem. However, few studies have been conducted on the natural regeneration necessary to restore these forests. We reviewed the ecology of regeneration of tropical dry forests as a tool to restore disturbed lands. Dry forests are characterized by a relatively high number of tree species with small, dry, wind-dispersed seeds. Over small scales, wind-dispersed seeds are better able to colonize degraded areas than vertebrate-dispersed plants. Small seeds and those with low water content are less susceptible to desiccation, which is a major barrier for establishment in open areas. Seeds are available in the soil in the early rainy season to maximize the time to grow. However, highly variable precipitation and frequent dry spells are important sources of mortality in seeds and seedlings. Collecting seeds at the end of the dry season and planting them when soil has sufficient moisture may increase seedling establishment and reduce the time they are exposed to seed predators. Germination and early establishment in the field are favored in shaded sites, which have milder environment and moister soil than open sites during low rainfall periods. Growth of established seedlings, however, is favored in open areas. Therefore, clipping plants around established seedlings may be a good management option to improve growth and survival. Although dry forests have species either resistant to fire or that benefit from it, frequent fires simplify community species composition. Resprouting ability is a noticeable mechanism of regeneration in dry forests and must be considered for restoration. The approach to dry-forest restoration should be tailored to this ecosystem instead of merely following approaches developed for moister forests.
With the increasing need to restore former agricultural lands worldwide and in the tropics, in pa... more With the increasing need to restore former agricultural lands worldwide and in the tropics, in particular, it is critical to explore different models for how to restore these lands in a cost-effective manner which best simulates natural forest recovery and provides for human livelihoods. We propose that agro-successional restoration, which we define as incorporating a range of agroecology and agroforestry techniques as a transition phase early in forest restoration, could be used more widely to overcome socioeconomic and ecological obstacles to restoring these lands. Over centuries, farmers and scientists have developed various agroforestry techniques that aim to cultivate crops and trees, in a range of crop types, time periods of cultivation (a few years to several decades), and complexity of species planted. The management practices used in these systems, such as weeding and increasing soil fertility, parallel those used in many forest restoration efforts. The synergism between these approaches is evidenced by many existing agro-successional examples currently used by smallholders in the tropics. Benefits of the agro-successional model include extending the management period of restoration, offsetting some management costs, providing food security for small landholders, and involving small landholders in the restoration process.
We studied the effect of forest gaps and cattle grazing on survival and growth of seedlings of se... more We studied the effect of forest gaps and cattle grazing on survival and growth of seedlings of seven native tree species, planted in dry forest fragments with different intensities of past logging in Central Brazil. Seedling survival after 12 mo ranged from 35 to 77 percent among species. Survival of most species was similar in gaps and understory in minimally disturbed forest remnants, but was lower in the gaps of more heavily logged forests. In contrast, growth was much higher in gaps than in understory in minimally disturbed forests, but for most species was similar in gaps and understory in more heavily logged forests. We did not detect an effect of cattle on seedling survival. Seedlings of the most commonly logged species show a high potential to survive and grow when planted in logged forests.Avaliamos os efeitos de clareiras e pastoreio de gado na sobrevivência e no crescimento de plântulas de sete espécies de árvores plantadas em fragmentos de florestas estacionais deciduais com diferentes intensidades de exploração madeireira no Brasil Central. A sobrevivência de plântulas após 12 meses variou de 35 a 77 porcento entre espécies. A sobrevivência da maioria das espécies foi semelhante em clareiras e sub-bosque em fragmentos pouco perturbados, mas foi menor nas grandes clareiras de um fragmento mais perturbado. Em contraste, o crescimento foi muito maior nas clareiras que no sub-bosque em florestas menos perturbadas, mas foi similar entre clareiras e sub-bosque nos fragmentos mais explorados. Nós não detectamos o efeito do gado na sobrevivência de plântulas. Plântulas das espécies mais comumente exploradas tiveram alto potencial para sobreviver e crescer quando plantadas em florestas exploradas.
Population structures of six tree species in three fragments of intact seasonal deciduous forest ... more Population structures of six tree species in three fragments of intact seasonal deciduous forest and three fragments disturbed by logging were studied in the northeastern Goiás. Forty random 400 m 2 plots were allocated in each fragment to survey plant population structures, number of stumps, cattle feces, burnt logs, and canopy openness. Soil cover by life forms was estimated in 1m 2 sub-plots. Lianas were abundant in intermediately logged fragments and invasive herbs in the most disturbed fragment. Cattle avoided dense herbaceous strata, such as liana tangles. Cavanillesia arborea, Eugenia dysenterica and Swartzia multijuga trees occurred at very low densities in all the fragments and their seedlings were practically absent, which might endanger their future populations in these fragments. Myracrodruon urundeuva, Tabebuia impetiginosa and Astronium fraxinifolium, the most logged species, had high density of seedlings in all the fragments. However, the highest density of saplings and juvenile individuals occurred in the most disturbed fragment.
Brazilian Archives of Biology and Technology, 2008
Population structures of six tree species in three fragments of intact seasonal deciduous forest ... more Population structures of six tree species in three fragments of intact seasonal deciduous forest and three fragments disturbed by logging were studied in the northeastern Goiás. Forty random 400 m2 plots were allocated in each fragment to survey plant population structures, number of stumps, cattle feces, burnt logs, and canopy openness. Soil cover by life forms was estimated in 1m2 sub-plots. Lianas were abundant in intermediately logged fragments and invasive herbs in the most disturbed fragment. Cattle avoided dense herbaceous strata, such as liana tangles. Cavanillesia arborea, Eugenia dysenterica and Swartzia multijuga trees occurred at very low densities in all the fragments and their seedlings were practically absent, which might endanger their future populations in these fragments. Myracrodruon urundeuva, Tabebuia impetiginosa and Astronium fraxinifolium, the most logged species, had high density of seedlings in all the fragments. However, the highest density of saplings and juvenile individuals occurred in the most disturbed fragment.
We assessed seed fate of six tree species in a seasonally deciduous forest of Central Brazil. See... more We assessed seed fate of six tree species in a seasonally deciduous forest of Central Brazil. Seed germination, predation, removal and death caused by pathogens or dessication were followed in an undisturbed forest site, a logged forest site, and an active pasture. In both forest types we sowed seeds under patches of liana tangles (Low Forest habitat) and under patches of mature forest (High Forest habitat). Seeds were monitored weekly for up to 8 months. Overall, small-seeded species (Astronium fraxinifolium and Tabebuia impetiginosa) had high germination, although germination was lower in the pasture due to insect predation. The hard-coated seeds of Erythrina sp. had higher germination rates in the pasture. The large-seeded Cavanillesia arborea and Swartzia multijuga had high seed removal (ca. 90%) in the pasture and under High Forest, but only 23-34% under Low Forest in the logged site. Lower removal of large seeds in Low Forest suggests that this habitat conceals the seeds and constrains the movement of large mammals. Both species were favored in Low Forest, suggesting that caution should be used when managing lianas. When protected from predation, seeds with a soft coat and high water content, such as the seeds of Eugenia dysenterica and S. multijuga, died from desiccation in the pasture. Restoration efforts must take into consideration high mortality caused by desiccation or insect predation in abandoned pastures of dry forests. #
A solid-phase extraction method combined with flow injection (FI) on-line flame atomic absorption... more A solid-phase extraction method combined with flow injection (FI) on-line flame atomic absorption spectrometry (FAAS) for the determination of cadmium and nickel in tobacco samples is presented. The 2-aminothiophenol functionalized Amberlite XAD-4 (AT-XAD) resin was synthesized by covalent coupling of the ligand with the copolymer through a methylene group. A minicolumn packed with AT-XAD was connected into the automated on-line preconcentration system. Elution of metal ions from minicolumn can be made with 0.50 mol L −1 hydrochloric acid solution. With a consumption of 21.0 mL of sample solution, detection limits (3 s) of 0.3 (Cd) and 0.8 g L −1 (Ni) were achieved at a sample throughput of 18 h −1 . Enrichment factors (EF) of 99 (cadmium) and 43 (nickel) were obtained compared with the slope of the linear portion of the calibration curves before and after preconcentration. The contents of Cd and Ni in a certified reference material (NIST 1570a, spinach leaves) determined by the present method was in good agreement with the certified value. The developed procedure was also successfully applied to the determination of Cd and Ni in local tobacco samples.
Cloud point extraction employing the new reagent 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydro... more Cloud point extraction employing the new reagent 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid as complexing agent and Triton X-114 as the surfactant is proposed for copper determination. A sample volume of 10 mL was used. Dilution of the surfactant-rich phase with acidified methanol was performed after phase separation, and the copper contents were measured by flame atomic absorption spectrometry. Variables affecting the system were optimized using factorial design and Doehlert matrix. Signals were measured as peak height using an instrument software. Using the experimental conditions defined in the optimization, the method allowed copper determination with a detection limit of 1.5 µg L−1. The calculated enrichment factor is 14. The effects of foreign ions are reported. The accuracy of the procedure was tested by analyzing certified reference material. The method was successfully applied to copper determination in natural and drinking water samples.
A new reagent, 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid (Me-... more A new reagent, 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid (Me-BDBD), was synthesised and used in on-line and off-line systems for copper preconcentration by solid-phase extraction. Spectrophotometry and Flame Atomic Absorption Spectrometry (FAAS) were the detection techniques. Polyurethane foam loaded with Me-BDBD packed in a minicolumn was used as sorbent in both systems. The spectral characteristics of Me-BDBD were investigated. The optimum pH values for maximum sorption of the metal are between 7.0 and 8.5. Copper was desorbed with 0.05 and 0.50 mol L−1 hydrochloric acid solutions, for on-line and off-line systems, respectively. The effects of several foreign substances on the adsorption of copper are reported. The enrichment factors obtained were 7 (on-line) and 26 (off-line) for the systems. The proposed procedures allowed the determination of copper with detection limits of 3.4 and 1.4 μg L−1 (0.85 and 0.35 μg per gram of sample) for on-line and off-line systems, respectively. The precision of the procedures was also calculated: 3.2 (on-line) and 1.9% (off-line). The validation of the procedures was carried out by analysis of certified reference material. The copper contents in corn and rice flour and black tea samples were determined by applying the proposed procedures.
RESUMO: Tanto a Análise Experimental do Comportamento, enquanto metodologia, como o Behaviorismo ... more RESUMO: Tanto a Análise Experimental do Comportamento, enquanto metodologia, como o Behaviorismo Radical, enquanto filosofia da ciência do comportamento, já estão consolidadas no meio acadêmico e científico da Psicologia e trazem tanto subsídios importantes para se desvendar o ser humano como técnicas de aplicação, possuindo um grande arsenal de conhecimento já estabelecido. No entanto, ainda nos dias de hoje, os professores que lecionam disciplinas relacionadas a esta abordagem relatam que ainda existe rejeição por parte de alunos e professores de cursos de Psicologia em relação a estes conteúdos, ao conhecimento real da abordagem e até mesmo em relação aos profissionais que pesquisam e/ou trabalham com esta área de conhecimento. Esta rejeição está embasada numa série de preconceitos e conceitos limitados e errôneos sobre o tema e traz dificuldades para o processo de ensinoaprendizagem. Para aprofundar a compreensão e melhorar a comunicação entre os analistas do comportamento e os profissionais de outras abordagens é preciso traçar alguns caminhos mais eficazes para a divulgação e o ensino da Análise do Comportamento e do Behaviorismo. Palavras-chave: Behaviorismo; análise do comportamento; Skinner.
Introduction Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decade... more Introduction Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decades, but inflammatory activation in this setting is still unpredictable and is associated with several postoperative complications. Perioperative levels of macrophage migration inhibitory factor (MIF) and other inflammatory mediators could be implicated in adverse outcomes in cardiac surgery. Methods Serum levels of MIF, monocyte chemoattractant protein (MCP)-1, soluble CD40 ligand, IL-6 and IL-10 from 93 patients subjected to CPB were measured by enzyme-linked immunosorbent assay and compared with specific and global postoperative organ dysfunctions through multiple organ dysfunction score (MODS) and sequential organ failure assessment (SOFA). Results Most of the cytokines measured had a peak of production between 3 and 6 hours after CPB, but maximum levels of MIF occurred earlier, at the cessation of CPB. Among specific organ dysfunctions, the most frequent was hematological, occurring in 82% of the patients. Circulatory impairment was observed in 73.1% of the patients, and 51% of these needed inotropics or vasopressors within the first 24 hours after surgery. The third most frequent dysfunction was pulmonary, occurring in 48.4% of the patients. Preoperative levels of MIF showed a relevant direct correlation with the intensity of global organ dysfunction measured by SOFA (ρ = 0.46, p < 0.001) and MODS (ρ = 0.50, p < 0.001) on the third day after surgery. MCP-1 production was associated with postoperative thrombocytopenia, and MIF was related to the use of a high dose of vasopressors in patients with cardiovascular impairment and also to lower values of the ratio of partial arterial oxygen tension (PaO2) to fraction of inspired oxygen (FiO2) registered in the first 24 hours after CPB. Conclusion Despite the multifactorial nature of specific or multiple organ dysfunctions, MIF should be explored as a predicting factor of organ dysfunction, or even as a potential therapeutic target in decreasing postoperative complications.
Page 1. Chapter 11 Recruitment of Dry Forest Tree Species in Central Brazil Pastures Aldicir Scar... more Page 1. Chapter 11 Recruitment of Dry Forest Tree Species in Central Brazil Pastures Aldicir Scariot, Daniel LM Vieira, Alexandre B. Sampaio, Ernestino Guarino and Anderson Sevilha 11.1 Introduction Despite its importance ...
Tropical dry forests are the most threatened tropical terrestrial ecosystem. However, few studies... more Tropical dry forests are the most threatened tropical terrestrial ecosystem. However, few studies have been conducted on the natural regeneration necessary to restore these forests. We reviewed the ecology of regeneration of tropical dry forests as a tool to restore disturbed lands. Dry forests are characterized by a relatively high number of tree species with small, dry, wind-dispersed seeds. Over small scales, wind-dispersed seeds are better able to colonize degraded areas than vertebrate-dispersed plants. Small seeds and those with low water content are less susceptible to desiccation, which is a major barrier for establishment in open areas. Seeds are available in the soil in the early rainy season to maximize the time to grow. However, highly variable precipitation and frequent dry spells are important sources of mortality in seeds and seedlings. Collecting seeds at the end of the dry season and planting them when soil has sufficient moisture may increase seedling establishment and reduce the time they are exposed to seed predators. Germination and early establishment in the field are favored in shaded sites, which have milder environment and moister soil than open sites during low rainfall periods. Growth of established seedlings, however, is favored in open areas. Therefore, clipping plants around established seedlings may be a good management option to improve growth and survival. Although dry forests have species either resistant to fire or that benefit from it, frequent fires simplify community species composition. Resprouting ability is a noticeable mechanism of regeneration in dry forests and must be considered for restoration. The approach to dry-forest restoration should be tailored to this ecosystem instead of merely following approaches developed for moister forests.
With the increasing need to restore former agricultural lands worldwide and in the tropics, in pa... more With the increasing need to restore former agricultural lands worldwide and in the tropics, in particular, it is critical to explore different models for how to restore these lands in a cost-effective manner which best simulates natural forest recovery and provides for human livelihoods. We propose that agro-successional restoration, which we define as incorporating a range of agroecology and agroforestry techniques as a transition phase early in forest restoration, could be used more widely to overcome socioeconomic and ecological obstacles to restoring these lands. Over centuries, farmers and scientists have developed various agroforestry techniques that aim to cultivate crops and trees, in a range of crop types, time periods of cultivation (a few years to several decades), and complexity of species planted. The management practices used in these systems, such as weeding and increasing soil fertility, parallel those used in many forest restoration efforts. The synergism between these approaches is evidenced by many existing agro-successional examples currently used by smallholders in the tropics. Benefits of the agro-successional model include extending the management period of restoration, offsetting some management costs, providing food security for small landholders, and involving small landholders in the restoration process.
We studied the effect of forest gaps and cattle grazing on survival and growth of seedlings of se... more We studied the effect of forest gaps and cattle grazing on survival and growth of seedlings of seven native tree species, planted in dry forest fragments with different intensities of past logging in Central Brazil. Seedling survival after 12 mo ranged from 35 to 77 percent among species. Survival of most species was similar in gaps and understory in minimally disturbed forest remnants, but was lower in the gaps of more heavily logged forests. In contrast, growth was much higher in gaps than in understory in minimally disturbed forests, but for most species was similar in gaps and understory in more heavily logged forests. We did not detect an effect of cattle on seedling survival. Seedlings of the most commonly logged species show a high potential to survive and grow when planted in logged forests.Avaliamos os efeitos de clareiras e pastoreio de gado na sobrevivência e no crescimento de plântulas de sete espécies de árvores plantadas em fragmentos de florestas estacionais deciduais com diferentes intensidades de exploração madeireira no Brasil Central. A sobrevivência de plântulas após 12 meses variou de 35 a 77 porcento entre espécies. A sobrevivência da maioria das espécies foi semelhante em clareiras e sub-bosque em fragmentos pouco perturbados, mas foi menor nas grandes clareiras de um fragmento mais perturbado. Em contraste, o crescimento foi muito maior nas clareiras que no sub-bosque em florestas menos perturbadas, mas foi similar entre clareiras e sub-bosque nos fragmentos mais explorados. Nós não detectamos o efeito do gado na sobrevivência de plântulas. Plântulas das espécies mais comumente exploradas tiveram alto potencial para sobreviver e crescer quando plantadas em florestas exploradas.
Population structures of six tree species in three fragments of intact seasonal deciduous forest ... more Population structures of six tree species in three fragments of intact seasonal deciduous forest and three fragments disturbed by logging were studied in the northeastern Goiás. Forty random 400 m 2 plots were allocated in each fragment to survey plant population structures, number of stumps, cattle feces, burnt logs, and canopy openness. Soil cover by life forms was estimated in 1m 2 sub-plots. Lianas were abundant in intermediately logged fragments and invasive herbs in the most disturbed fragment. Cattle avoided dense herbaceous strata, such as liana tangles. Cavanillesia arborea, Eugenia dysenterica and Swartzia multijuga trees occurred at very low densities in all the fragments and their seedlings were practically absent, which might endanger their future populations in these fragments. Myracrodruon urundeuva, Tabebuia impetiginosa and Astronium fraxinifolium, the most logged species, had high density of seedlings in all the fragments. However, the highest density of saplings and juvenile individuals occurred in the most disturbed fragment.
Brazilian Archives of Biology and Technology, 2008
Population structures of six tree species in three fragments of intact seasonal deciduous forest ... more Population structures of six tree species in three fragments of intact seasonal deciduous forest and three fragments disturbed by logging were studied in the northeastern Goiás. Forty random 400 m2 plots were allocated in each fragment to survey plant population structures, number of stumps, cattle feces, burnt logs, and canopy openness. Soil cover by life forms was estimated in 1m2 sub-plots. Lianas were abundant in intermediately logged fragments and invasive herbs in the most disturbed fragment. Cattle avoided dense herbaceous strata, such as liana tangles. Cavanillesia arborea, Eugenia dysenterica and Swartzia multijuga trees occurred at very low densities in all the fragments and their seedlings were practically absent, which might endanger their future populations in these fragments. Myracrodruon urundeuva, Tabebuia impetiginosa and Astronium fraxinifolium, the most logged species, had high density of seedlings in all the fragments. However, the highest density of saplings and juvenile individuals occurred in the most disturbed fragment.
We assessed seed fate of six tree species in a seasonally deciduous forest of Central Brazil. See... more We assessed seed fate of six tree species in a seasonally deciduous forest of Central Brazil. Seed germination, predation, removal and death caused by pathogens or dessication were followed in an undisturbed forest site, a logged forest site, and an active pasture. In both forest types we sowed seeds under patches of liana tangles (Low Forest habitat) and under patches of mature forest (High Forest habitat). Seeds were monitored weekly for up to 8 months. Overall, small-seeded species (Astronium fraxinifolium and Tabebuia impetiginosa) had high germination, although germination was lower in the pasture due to insect predation. The hard-coated seeds of Erythrina sp. had higher germination rates in the pasture. The large-seeded Cavanillesia arborea and Swartzia multijuga had high seed removal (ca. 90%) in the pasture and under High Forest, but only 23-34% under Low Forest in the logged site. Lower removal of large seeds in Low Forest suggests that this habitat conceals the seeds and constrains the movement of large mammals. Both species were favored in Low Forest, suggesting that caution should be used when managing lianas. When protected from predation, seeds with a soft coat and high water content, such as the seeds of Eugenia dysenterica and S. multijuga, died from desiccation in the pasture. Restoration efforts must take into consideration high mortality caused by desiccation or insect predation in abandoned pastures of dry forests. #
A solid-phase extraction method combined with flow injection (FI) on-line flame atomic absorption... more A solid-phase extraction method combined with flow injection (FI) on-line flame atomic absorption spectrometry (FAAS) for the determination of cadmium and nickel in tobacco samples is presented. The 2-aminothiophenol functionalized Amberlite XAD-4 (AT-XAD) resin was synthesized by covalent coupling of the ligand with the copolymer through a methylene group. A minicolumn packed with AT-XAD was connected into the automated on-line preconcentration system. Elution of metal ions from minicolumn can be made with 0.50 mol L −1 hydrochloric acid solution. With a consumption of 21.0 mL of sample solution, detection limits (3 s) of 0.3 (Cd) and 0.8 g L −1 (Ni) were achieved at a sample throughput of 18 h −1 . Enrichment factors (EF) of 99 (cadmium) and 43 (nickel) were obtained compared with the slope of the linear portion of the calibration curves before and after preconcentration. The contents of Cd and Ni in a certified reference material (NIST 1570a, spinach leaves) determined by the present method was in good agreement with the certified value. The developed procedure was also successfully applied to the determination of Cd and Ni in local tobacco samples.
Cloud point extraction employing the new reagent 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydro... more Cloud point extraction employing the new reagent 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid as complexing agent and Triton X-114 as the surfactant is proposed for copper determination. A sample volume of 10 mL was used. Dilution of the surfactant-rich phase with acidified methanol was performed after phase separation, and the copper contents were measured by flame atomic absorption spectrometry. Variables affecting the system were optimized using factorial design and Doehlert matrix. Signals were measured as peak height using an instrument software. Using the experimental conditions defined in the optimization, the method allowed copper determination with a detection limit of 1.5 µg L−1. The calculated enrichment factor is 14. The effects of foreign ions are reported. The accuracy of the procedure was tested by analyzing certified reference material. The method was successfully applied to copper determination in natural and drinking water samples.
A new reagent, 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid (Me-... more A new reagent, 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid (Me-BDBD), was synthesised and used in on-line and off-line systems for copper preconcentration by solid-phase extraction. Spectrophotometry and Flame Atomic Absorption Spectrometry (FAAS) were the detection techniques. Polyurethane foam loaded with Me-BDBD packed in a minicolumn was used as sorbent in both systems. The spectral characteristics of Me-BDBD were investigated. The optimum pH values for maximum sorption of the metal are between 7.0 and 8.5. Copper was desorbed with 0.05 and 0.50 mol L−1 hydrochloric acid solutions, for on-line and off-line systems, respectively. The effects of several foreign substances on the adsorption of copper are reported. The enrichment factors obtained were 7 (on-line) and 26 (off-line) for the systems. The proposed procedures allowed the determination of copper with detection limits of 3.4 and 1.4 μg L−1 (0.85 and 0.35 μg per gram of sample) for on-line and off-line systems, respectively. The precision of the procedures was also calculated: 3.2 (on-line) and 1.9% (off-line). The validation of the procedures was carried out by analysis of certified reference material. The copper contents in corn and rice flour and black tea samples were determined by applying the proposed procedures.
RESUMO: Tanto a Análise Experimental do Comportamento, enquanto metodologia, como o Behaviorismo ... more RESUMO: Tanto a Análise Experimental do Comportamento, enquanto metodologia, como o Behaviorismo Radical, enquanto filosofia da ciência do comportamento, já estão consolidadas no meio acadêmico e científico da Psicologia e trazem tanto subsídios importantes para se desvendar o ser humano como técnicas de aplicação, possuindo um grande arsenal de conhecimento já estabelecido. No entanto, ainda nos dias de hoje, os professores que lecionam disciplinas relacionadas a esta abordagem relatam que ainda existe rejeição por parte de alunos e professores de cursos de Psicologia em relação a estes conteúdos, ao conhecimento real da abordagem e até mesmo em relação aos profissionais que pesquisam e/ou trabalham com esta área de conhecimento. Esta rejeição está embasada numa série de preconceitos e conceitos limitados e errôneos sobre o tema e traz dificuldades para o processo de ensinoaprendizagem. Para aprofundar a compreensão e melhorar a comunicação entre os analistas do comportamento e os profissionais de outras abordagens é preciso traçar alguns caminhos mais eficazes para a divulgação e o ensino da Análise do Comportamento e do Behaviorismo. Palavras-chave: Behaviorismo; análise do comportamento; Skinner.
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