RESUMO
The present study aimed was to evaluate the spatial variability of weed species by means of phytosociological parameters and their correlations with the physical-chemical soil properties, under semiarid climate conditions. Weed phytosociology and soil characterization were carried out in two areas one newly deforested area covering 8.86 ha, and one experimental agricultural area covering 24.7 ha; both in the semi-arid region of Brazil. Weed and soil were sampled by following georeferenced grids in each area. Biomass and the total number of weed individuals, as well as soil properties, were mapped by the ordinary Kriging method. The predominant herbaceous plants in the newly deforested area were Hexasepalum teres and Digitaria insularis. The weed species that predominated in the agricultural area were Cyperus rotundus L., Euphorbia heterophylla L. and Herissantia Crispa (L.) Brizicky; the latter species outstanding for dry biomass (873.5g). Spatial dependence was observed for the predominant species, except for Digitaria insularis. The spatial distribution of these weeds was conditioned by soil K+ contents in both areas, and by sand content for the experimental agricultural area. Therefore, these two soil attributes resulted key factors for weed infestation in this semi-arid region.
Assuntos
Agricultura , Solo , Humanos , Solo/química , Brasil , Agricultura/métodos , Plantas Daninhas , BiomassaRESUMO
Although studies aimed at understanding entrepreneurship have analyzed passion, creativity, and entrepreneurial self-efficacy, few studies include these antecedents in the same model. In this sense, this study aims to assess the relationship between passion, self-efficacy, and creativity with entrepreneurial intention. The data was collected through a survey and the questionnaires were applied to university students who formed a sample of 190 respondents, and such data was analyzed using structural equation modeling based on partial least square technique. Regarding our results, the relationship between creativity and entrepreneurial intention has not been confirmed. The multigroup analysis revealed that the level of education influences men's entrepreneurial intention and creativity only influence entrepreneurial intention when mediated by entrepreneurial passion. This study contributes by highlighting the roles of analyzed passion, creativity, and entrepreneurial self-efficacy in entrepreneurs from one of the largest emerging economies in the world. Moreover, it also contributes to academia as it confirms the explanatory power of the Theory of Planned Behavior as a tool to understand the cognitive foundations of entrepreneurship. It also offers a practical contribution by signaling to public policymakers which features should be incentivized to boost entrepreneurship in emerging economies.
RESUMO
BACKGROUND: Headache is a very common complaint and it is increasingly prevalent among university students. Tinnitus consists of subjectively perceived sounds that occur in the absence of an external auditory signal. Presence of headache and tinnitus in association has implications for therapy and prognosis, because this describes the temporality of the symptoms. Recognition of the epidemiological profile of symptomatic students might contribute to interventions. OBJECTIVE: To investigate the prevalence of the association between headache and tinnitus, and to describe the epidemiological profile of the study population and the chronological order of appearance of these symptoms. METHODS: Cross-sectional, observational and analytical study on a sample representative of an academic center. Data referring to the epidemiological and clinical profile of headache and tinnitus among medical students were collected through an online questionnaire built using the Google Forms tool. RESULTS: Out of the 234 participants, 26.1% reported having tinnitus and headache (p < 0.001). The participants with headache were more likely to be women (p = 0.045), white (p = 0.009) and 21-25 years old (p = 0.356). Among right-sided, left-sided and non-unilateral headaches, tinnitus was present predominantly in the non-unilateral type, but without statistical significance. Regarding timing, 18.0% of the students said that tinnitus started before headache, 57.4% said that headache started before tinnitus and 24.6% said that they started simultaneously. CONCLUSIONS: An important association between headache and tinnitus regarding lateralization and temporality was demonstrated. Thus, these data match the presumption that headache and tinnitus have a physiopathological connection.
Assuntos
Estudantes de Medicina , Zumbido , Estudos Transversais , Feminino , Cefaleia/epidemiologia , Humanos , Prevalência , Zumbido/epidemiologiaRESUMO
ABSTRACT Background: Headache is a very common complaint and it is increasingly prevalent among university students. Tinnitus consists of subjectively perceived sounds that occur in the absence of an external auditory signal. Presence of headache and tinnitus in association has implications for therapy and prognosis, because this describes the temporality of the symptoms. Recognition of the epidemiological profile of symptomatic students might contribute to interventions. Objective: To investigate the prevalence of the association between headache and tinnitus, and to describe the epidemiological profile of the study population and the chronological order of appearance of these symptoms. Methods: Cross-sectional, observational and analytical study on a sample representative of an academic center. Data referring to the epidemiological and clinical profile of headache and tinnitus among medical students were collected through an online questionnaire built using the Google Forms tool. Results: Out of the 234 participants, 26.1% reported having tinnitus and headache (p < 0.001). The participants with headache were more likely to be women (p = 0.045), white (p = 0.009) and 21-25 years old (p = 0.356). Among right-sided, left-sided and non-unilateral headaches, tinnitus was present predominantly in the non-unilateral type, but without statistical significance. Regarding timing, 18.0% of the students said that tinnitus started before headache, 57.4% said that headache started before tinnitus and 24.6% said that they started simultaneously. Conclusions: An important association between headache and tinnitus regarding lateralization and temporality was demonstrated. Thus, these data match the presumption that headache and tinnitus have a physiopathological connection.
RESUMO Antecedentes: A cefaleia é uma queixa muito frequente e a prevalência em estudantes universitários vem sendo cada vez mais comum. Os zumbidos constituem percepções subjetivas de sons que acontecem na ausência de um sinal auditivo externo ou não. A correlação desses sintomas é importante para fins terapêuticos e prognóstico, pois descrever a temporalidade dos sintomas e conhecer o perfil epidemiológico dos estudantes sintomáticos pode contribuir com intervenções. Objetivo: Investigar a prevalência da relação da cefaleia e zumbido, descrever o perfil epidemiológico da população estudada e a ordem temporal do aparecimento desses dois sintomas. Métodos: Estudo de corte transversal, observacional e analítico representativo de um centro acadêmico. Foram coletados dados referentes ao perfil epidemiológico e clínico da cefaleia e zumbido entre acadêmicos de Medicina, por meio de um questionário online construído na ferramenta Google Forms. Resultados: Dos 234 participantes, 26,1% relataram a presença de zumbido e cefaleia. Os participantes com cefaleia apresentaram maior probabilidade de serem mulheres, da raça branca e ter entre 21-25 anos. Dentre as cefaleias sem unilateralidade, as localizadas à direita e as localizadas à esquerda, o zumbido predominou no tipo sem unilateralidade, entretanto sem significância estatística. Observou-se que 18,0% dos acadêmicos relataram o início do zumbido antes da cefaleia, 57,4% relataram o início da cefaleia antes do zumbido, e 24,6% início simultâneo. Conclusões: Foi demonstrada uma importante relação entre cefaleia e zumbido acerca da lateralidade e temporalidade. Assim, esses dados se encaixam na presunção de que a cefaleia e o zumbido possuem uma ligação fisiopatológica.
Assuntos
Humanos , Feminino , Estudantes de Medicina , Zumbido/epidemiologia , Prevalência , Estudos Transversais , Cefaleia/epidemiologiaRESUMO
The rise of the mosquitoes-transmitted diseases, like dengue, zika and chikungunya in Brazil in the last years has increased concerns on protection against mosquitoes bites. However, the prohibitive prices of the commercially available repellents for the majority of the Brazilian population has provoked a search for cheaper solutions, like the use of the homemade ethanolic extract of Indian clove (Syzygium aromaticum L.) as repellent, which has been reported as quite efficient by the local press. In order to verify this, we performed here the quantification of the main components of this extract through high-performance thin-layer chromatography (HPTLC)-densitometry and evaluated its efficiency as a repellent and its acetylcholinesterase (AChE) inhibition capacity. Our results have proved HPTLC-densitometry as an efficient and appropriate method for this quantification and confirmed the repellency activity, as well as its capacity of AChE inhibition.
Assuntos
Inibidores da Colinesterase , Cromatografia em Camada Fina/métodos , Repelentes de Insetos , Extratos Vegetais , Syzygium/química , Acetilcolinesterase/metabolismo , Adulto , Aedes/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Inibidores da Colinesterase/análise , Inibidores da Colinesterase/química , Inibidores da Colinesterase/farmacologia , Densitometria , Eugenol/análise , Eugenol/química , Eugenol/farmacologia , Humanos , Repelentes de Insetos/análise , Repelentes de Insetos/química , Repelentes de Insetos/farmacologia , Limite de Detecção , Modelos Lineares , Masculino , Extratos Vegetais/análise , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Reprodutibilidade dos Testes , Adulto JovemRESUMO
ABSTRACT This study aims the anatomical description and chemical characterization of aerial parts of Clusia criuva Cambess., Clusiaceae in addition to the evaluation of the antioxidant activity of crude extracts, correlated to the flavonoid content. The morphological characterization was performed using traditional techniques of plant anatomy. For phytochemical studies, crude extracts were obtained by static maceration and analyzed by thin layer chromatography. The antioxidant activity and the flavonoids content were determined by colorimetric methods involving, respectively, 2,2-diphenyl-1-picrylhydrazyl free radical and aluminum chloride. C. criuva has uniseriate epidermis, paracytic stomata, hypostomatic leaves, cuticular flanges and cordiform vascular cylinder with accessory bundles. Chemical prospecting confirmed the abundant presence of terpenes and phenols in the extracts of leaves and of fruits. The methanolic extract of seeds showed the lowest EC50 value, but the methanolic extract of pericarps exhibited the highest maximum antioxidant activity. The results suggested a high percentage of flavonoids in the hexanic extract of pericarps, however, this could represent, in fact, the presence of benzophenones. Secretory ducts and the shape of the midrib are diagnostic for C. criuva. The antioxidant activity is not directly related to the flavonoids. The results indicate the importance of future studies with C. criuva chemical constituents.
Assuntos
Extratos Vegetais/química , Clusia/química , Antioxidantes/química , Microscopia Eletrônica de Varredura , Cromatografia em Camada Fina , Colorimetria , Folhas de Planta/ultraestrutura , Folhas de Planta/química , Clusia/classificação , Clusia/ultraestrutura , Antioxidantes/isolamento & purificaçãoRESUMO
This study aims the anatomical description and chemical characterization of aerial parts of Clusia criuva Cambess., Clusiaceae in addition to the evaluation of the antioxidant activity of crude extracts, correlated to the flavonoid content. The morphological characterization was performed using traditional techniques of plant anatomy. For phytochemical studies, crude extracts were obtained by static maceration and analyzed by thin layer chromatography. The antioxidant activity and the flavonoids content were determined by colorimetric methods involving, respectively, 2,2-diphenyl-1-picrylhydrazyl free radical and aluminum chloride. C. criuva has uniseriate epidermis, paracytic stomata, hypostomatic leaves, cuticular flanges and cordiform vascular cylinder with accessory bundles. Chemical prospecting confirmed the abundant presence of terpenes and phenols in the extracts of leaves and of fruits. The methanolic extract of seeds showed the lowest EC50 value, but the methanolic extract of pericarps exhibited the highest maximum antioxidant activity. The results suggested a high percentage of flavonoids in the hexanic extract of pericarps, however, this could represent, in fact, the presence of benzophenones. Secretory ducts and the shape of the midrib are diagnostic for C. criuva. The antioxidant activity is not directly related to the flavonoids. The results indicate the importance of future studies with C. criuva chemical constituents.
Assuntos
Antioxidantes/química , Clusia/química , Extratos Vegetais/química , Antioxidantes/isolamento & purificação , Cromatografia em Camada Fina , Clusia/classificação , Clusia/ultraestrutura , Colorimetria , Microscopia Eletrônica de Varredura , Folhas de Planta/química , Folhas de Planta/ultraestruturaRESUMO
O conhecimento dos aspectos que envolvem todo o mecanismo do processo de germinação de sementes em espécies florestais ainda se encontra muito aquém em comparação com as espécies cultivadas. Objetivou-se estudar a influência da localização da semente no fruto sobre a germinação e crescimento de plântulas de tamboril (Enterolobium contortisiliquum) sob dois regimes de temperatura. Foram separadas as sementes das regiões proximal, central e distal do fruto. As sementes de cada região foram submetidas aos testes de primeira contagem, porcentagem final e índice de velocidade de germinação, em dois regimes de temperatura (25 °C constante e 2030 °C alternados), além do envelhecimento acerado. As plântulas provenientes desses testes foram analisadas pelas determinações do comprimento e massa seca da parte aérea, raiz e total. O experimento foi conduzido em delineamento inteiramente casualizado, seguindo um esquema fatorial 3x2 (três regiões e duas temperaturas) com quatro repetições. Os dados com distribuição normal foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey (5%); quando não normal utilizou-se o teste não paramétrico de Mann-Whitney (5%). Houve interação dos fatores para o índice de velocidade de germinação, comprimento total, massa seca total e massa seca da parte aérea das plântulas. Não se observou diferenças entre as localizações para as variáveis de avaliação das plântulas. Quanto à germinação, sob 25 °C as sementes da região distal do fruto germinaram mais rapidamente. Independente dos tratamentos a porcentagem de germinação foi sempre superior a 95%, mesmo quando envelhecidas. Conclui-se que não há diferença entre as temperaturas de 25 e 20-30 °C para a germinação de tamboril; que a localização das sementes no fruto não influencia na formação das plântulas; e que a velocidade de germinação e o crescimento das plântulas provenientes de sementes das regiões proximal e distal são mais sensíveis às mudanças de temperatura.
The knowledge of the aspects involving the entire mechanism of the process of seed germination in forest species is still far below in comparison with the cultivated species. It was aimed to study the influence of the seed location in the fruit in germination and seedling growth of "tamboril" (Enterolobium contorsiliquum (Vell.) Morong) under two temperature regimes. Were separated the seeds from the proximal, central and distal regions of the fruit. The seeds of each region were submitted to first count, final percentage and germination rate test, in two temperature regimes (25 °C constant and 20-30 °C alternate), beyond accelerated aging. The seedlings from these tests were analyzed by determination of the shoot, root and total length and dry weight. The experiment was conducted in completely randomized design, following the factorial scheme 3x2 (three locations and two temperatures) with four replication. The data with normal distribution were submitted to variance analysis and the averages compared by Tukey test (5%); when no normal was used Mann-Whitney test (5%). There was interaction of factors to germination rate, total length and shoot and total dry weight. Wasn't note differences between the locations to the variables of seedling evaluating. For germination, under 25 °C the distal seed of the fruit germinated faster. Independent treatments the germination percentage was always over 95%, even when aged. Concludes that don't exist difference between 25 and 20-30 °C to "tamboril" seed germination; that the seed location in the fruit doesn't influence in the seedling formation; and that the germination rate and the seedling growth from proximal and distal seeds are more sensitive to temperature change.
Assuntos
Germinação , Plântula/crescimento & desenvolvimento , Sementes , ÁrvoresRESUMO
The work had as objective to do a morphometric characterization of the fruits and seeds, to identify the best treatments to overcome dormancy, identify the best temperature for germination and also evaluate adequate conditions for storing the seeds of Caesalpinia pulcherrima (L.), which is a specie used for live fences, windbreakers, medicinal applications and urban landscaping. It was determined the biometrics measurements (length, width end thickness) and embryo type, weight of 1000 seeds, number of seeds per fruit, color, shape and micropyle and hlium position. It was evaluated the effect of different treatments to dormancy overcome, temperatures of germination and storing conditions. The experimental procedures used were completely randomized with four repetitions of 25 seeds. The fruit of C. pulcherrima is a type of legume, dehiscent, polyspermic, with an average of 7 seeds per unit, which have an oblong-oval format, axial embryo, with 9.6 mm of length, 7.3 mm of width and 3.3 mm of thickness. The mechanical scarification of the seeds on the opposite side of the micropyle and temperature of 30C provided the best results for germination. The physiological quality of the seeds was maintained for 270 days when the seeds were stored with 7% of moisture content independent of the package and storing conditions.
O objetivo foi caracterizar a morfometria de frutos e sementes, identificar o melhor tratamento de superação de dormência, a melhor temperatura de germinação e avaliar o potencial de armazenamento de sementes de Caesalpinia pulcherrima, uma espécie arbóreo-arbustiva, utilizada como cerca viva, quebra vento e de amplo uso medicinal e paisagístico. Para a caracterização morfométrica, determinouse o comprimento, espessura, largura, massa de 1000 sementes, número de sementes por fruto, coloração, formato e localização do hilo e da micrópila, tipo de embrião, sua localização e tipo de germinação. A qualidade fisiológica das sementes foi avaliada em função de diferentes tratamentos de superação de dormência, temperaturas e condições de armazenamento. Os ensaios foram instalados sob delineamento inteiramente casualizado, com quatro repetições de 25 sementes. O fruto é do tipo legume, deiscente, polispérmico, contendo em média sete sementes, que apresentam formato oblongo-ovalado, embrião axial linear, com 9,6 mm de comprimento, 7,3 mm de largura por 3,3 mm de espessura. A escarificação mecânica das sementes em lado oposto à micrópila e a temperatura de 300C constituíram no melhor tratamento germinativo. A qualidade fisiológica das sementes foi mantida por 270 dias, quando armazenadas com grau de umidade de 7%, independente da embalagem e condições de armazenamento.
Assuntos
Caesalpinia/crescimento & desenvolvimento , Dormência de Plantas , Sementes/crescimento & desenvolvimento , Armazenamento de ProdutosRESUMO
The work had as objective to do a morphometric characterization of the fruits and seeds, to identify the best treatments to overcome dormancy, identify the best temperature for germination and also evaluate adequate conditions for storing the seeds of Caesalpinia pulcherrima (L.), which is a specie used for live fences, windbreakers, medicinal applications and urban landscaping. It was determined the biometrics measurements (length, width end thickness) and embryo type, weight of 1000 seeds, number of seeds per fruit, color, shape and micropyle and hlium position. It was evaluated the effect of different treatments to dormancy overcome, temperatures of germination and storing conditions. The experimental procedures used were completely randomized with four repetitions of 25 seeds. The fruit of C. pulcherrima is a type of legume, dehiscent, polyspermic, with an average of 7 seeds per unit, which have an oblong-oval format, axial embryo, with 9.6 mm of length, 7.3 mm of width and 3.3 mm of thickness. The mechanical scarification of the seeds on the opposite side of the micropyle and temperature of 30C provided the best results for germination. The physiological quality of the seeds was maintained for 270 days when the seeds were stored with 7% of moisture content independent of the package and storing conditions.(AU)
O objetivo foi caracterizar a morfometria de frutos e sementes, identificar o melhor tratamento de superação de dormência, a melhor temperatura de germinação e avaliar o potencial de armazenamento de sementes de Caesalpinia pulcherrima, uma espécie arbóreo-arbustiva, utilizada como cerca viva, quebra vento e de amplo uso medicinal e paisagístico. Para a caracterização morfométrica, determinouse o comprimento, espessura, largura, massa de 1000 sementes, número de sementes por fruto, coloração, formato e localização do hilo e da micrópila, tipo de embrião, sua localização e tipo de germinação. A qualidade fisiológica das sementes foi avaliada em função de diferentes tratamentos de superação de dormência, temperaturas e condições de armazenamento. Os ensaios foram instalados sob delineamento inteiramente casualizado, com quatro repetições de 25 sementes. O fruto é do tipo legume, deiscente, polispérmico, contendo em média sete sementes, que apresentam formato oblongo-ovalado, embrião axial linear, com 9,6 mm de comprimento, 7,3 mm de largura por 3,3 mm de espessura. A escarificação mecânica das sementes em lado oposto à micrópila e a temperatura de 300C constituíram no melhor tratamento germinativo. A qualidade fisiológica das sementes foi mantida por 270 dias, quando armazenadas com grau de umidade de 7%, independente da embalagem e condições de armazenamento.(AU)