The paper offers an interpretation of David Hilbert's contributions to the theory of polygonal magnitudes, developed in his influential monograph Foundations of Geometry, published in 1899. It is argued that the construction of this central part of Euclidean geometry presented an appealing challenge to Hilbert's general aim of providing a purely synthetic axiomatization of this geometrical theory; in other words, to his epistemological and methodological concerns of constructing elementary geometry without resorting to any kind of numerical assumption. Moreover, it is claimed this challenge consisted in offering a new foundation for the theory of polygonal area, which could be considered at the same time as logically sound and purely geometrical.

El artículo ofrece una interpretación de las contribuciones de David Hilbert a la teoría de las magnitudes poligonales, desarrollada en su influyente monografía Fundamentos de la geometría, publicada en 1899. Se argumenta que la construcción de esta parte central de la geometría euclidiana represento para Hilbert un desafío muy significativo, en razón de su objetivo general de proporcionar una axiomatización estrictamente sintética de esta teoría geométrica; es decir, en virtud de sus conocidos requerimientos metodológicos y epistemológicos de construir la geometría elemental evitando toda apelación esencial a presupuestos numéricos. Se sostiene además que dicho desafío consistió en ofrecer un nuevo fundamento lógicamente sólido para la teoría del área poligonal, pero que al mismo tiempo pueda ser considerado como puramente geométrico.

A internet causou uma verdadeira revolução no marketing boca-a-boca. Essa comunicação, que antes demandava o contato pessoal, agora é compartilhada globalmente por meio de plataformas virtuais entre indivíduos desconhecidos e geograficamente dispersos. O objetivo deste estudo é avaliar os fatores que afetam a adoção de informações em comunidades de consumidores online. Com uma amostra de 288 respondentes, os dados obtidos foram analisados por meio da modelagem de equações estruturais. Os resultados apontam que a percepção de utilidade das informações se mostrou importante para o processo de adoção das opiniões, sendo a relevância e a confiabilidade da fonte os fatores que mais influenciaram a utilidade percebida.

Internet has revolutionized word-of-mouth marketing. Once face-to-face, word-of-mouth communications can now be exchanged globally via a multitude of platforms, allowing virtual strangers to share information regardless of geographical boundaries. This study aims to evaluate factors affecting the adoption of information among members of online consumer communities. Structural Equation Modelling (SEM) was used to analyze data from a 288 respondent sample acquired via survey and results indicate that information utility, majorly driven by its relevance and reliability, is crucial for information adoption processes.

The paper examines one the most important contributions to the foundations of elementary Euclidean geometry achieved by David Hilbert in his book Foundations of Geometry (1899), namely the reconstruction of the Euclidean theory of proportion and similar triangles. It is argued that this reconstruction was not only motived by Hilbert's identification of implicit assumptions in Euclid's theory, but also it was essentially linked to the concern for the 'purity of methods'. Moreover, it is claimed that in this specific case, Hilbert's requirement of the purity of method has a general or foundational dimension, that is, it is not established with regard to the proof of a particular theorem, but rather it is referred to the very axiomatic construction of the theory.

El artículo examina una de las contribuciones más importantes a los fundamentos de la geometría euclídea elemental lograda por David Hilbert en su obra Fundamentos de la geometría (1899), a saber: la reconstrucción de la teoría euclídea de las proporciones y de los triángulos semejantes. Se argumenta que dicha reconstrucción no sólo estuvo motivada por la identificación de Hilbert de suposiciones implícitas en la teoría de Euclides, sino que además estuvo esencialmente ligada a la preocupación por la 'pureza del método'. Más aún, se afirma que, en este caso específico, el requerimiento de Hilbert por la pureza del método posee un carácter general o fundacional, esto es, no se refiere a la demostración de un teorema en particular, sino más bien es planteado respecto de la construcción axiomática de la teoría misma.

On the basis of a set of unpublished notes for lecture courses on geometry, the paper seeks to contextualize and analyze one of the most important and original contributions of David Hilbert's celebrated monograph Foundations of Geometry (1899), namely its arithmetic of line segments (Streckenrechnungen). It is argued that Hilbert attributed to his arithmetic of segments an important epistemological and methodological meaning, in addition to its relevance as an original mathematical result. In particular, it is claimed that for Hilbert his arithmetic of segments represented a clear example of one of the most fruitful and attractive traits of his new formal axiomatic method, i.e., the power to discover and exhibit inner or structural connections among different mathematical theories.

Sobre la base que aportan las notas manuscritas de David Hilbert para cursos sobre geometría, el artículo procura contextualizar y analizar una de las contribuciones más importantes y novedosas de su célebre monografía Fundamentos de la geometría (1899), a saber: el cálculo de segmentos lineales (Streckenrechnungen). Se argumenta que, además de ser un resultado matemático importante, Hilbert depositó en su aritmética de segmentos un destacado significado epistemológico y metodológico. En particular, se afirma que para Hilbert este resultado representaba un claro ejemplo de uno de los rasgos más fructíferos y atractivos de su nuevo método axiomático formal, o sea, la capacidad de descubrir y exhibir conexiones estructurales o internas entre diferentes teorías matemáticas.

A fertilização dos solos com adubos orgânicos tem adquirido importância do ponto de vista da concepção de produção vegetal sustentável. Foi objetivo deste trabalho avaliar os efeitos de dosagens de esterco bovino e avícola em Achillea millefolium L. no crescimento vegetativo, teor e composição química do óleo essencial. Na fertilização com o esterco bovino avaliaram-se as doses: 1) Solo sem adubação; 2) solo + 3,0 kg m-2; 3) solo + 6,0 kg m-2; 4) solo + 9,0 kg m-2; 5) solo + 12,0 kg m-2. Na adubação com esterco avícola: 1) solo sem adubação; 2) solo + 1,5 kg m-2; 3) solo + 3,0 kg m-2; 4) solo + 4,5 kg m-2 e 5) solo + 6,0 kg m-2. O delineamento experimental utilizado foi o inteiramente casualizado com quatro repetições por tratamento e quatro plantas por parcela experimental. A colheita ocorreu aos 110 dias e avaliaram-se as biomassas secas da parte aérea e raiz, razão raiz/parte aérea, teor, rendimento e composição química do óleo essencial. Os dados foram submetidos à análise de variância e de regressão. A. millefolium responde com maior intensidade a adubação com esterco avícola que com a bovina, onde a dose de 6 kg m-2 apresentou o maior acúmulo de biomassa seca da parte aérea e maior rendimento de óleo essencial. Independente da adubação das plantas, o óleo essencial da A. millefolium é constituído majoritariamente por camazuleno e os tratamentos aplicados não interferiram expressivamente na composição e teor dos constituintes químicos do óleo.

Fertilization of the soil with organic fertilizers has been gaining importance within the concept of sustainable crop production. This study aimed evaluates the effects of dosages of cattle and poultry manure on Achillea millefolium L. as regards the vegetative growth and the content and chemical composition of its essential oil. For the cattle manure fertilization the dosages evaluated were: 1) soil with no fertilizer; 2) soil + 3.0 kg m-2; 3) soil + 6.0 kg m-2; 4) soil + 9.0 kg m-2 and 5) soil + 12.0 kg m-2. For fertilization with poultry manure: 1) soil without fertilizer; 2) soil + 1.5 kg m-2; 3) soil + 3.0 kg m-2; 4) soil + 4.5 kg m-2 and 5) soil + 6.0 kg m-2. The experimental design was completely randomized, with four replications per treatment and four plants per experimental plot. Harvesting took place at 110 days and the following variables were measured: shoot and root dry biomass; root to shoot ratio and the content, yield and chemical composition of the essential oil. Data were submitted to variance and regression analyses. A. millefolium has more intense response in fertilization with poultry manure than to that of cattle, where the dosage of 6 kg m-2 presented the greatest shoot dry weight and highest yield of essential oil. Without regard to fertilization, the essential oil of A. millefolium consists mainly of chamazulene, with the applied treatments not significantly interfering in the oil chemical composition and content.

Mentha x piperita L. é uma planta aromática e medicinal pertencente à família Lamiaceae, popularmente conhecida como hortelã-pimenta. No trabalho, objetivou-se verificar o efeito das fontes de adubação orgânica na produção de biomassa, no rendimento e na composição química do óleo essencial de hortelã-pimenta (Mentha piperita L.). O experimento foi conduzido em DIC, em esquema fatorial 2 x 5, com duas fontes de esterco, bovino e avícola, e cinco doses (0, 3, 6, 9 e 12 kg m-2), com quatro repetições cada. As diferentes doses de estercos bovino e avícola influenciaram significativamente de forma benéfica a produção de biomassa das plantas e também outras variáveis de crescimento como área foliar, razão de peso foliar, razão de área foliar, relação raiz:parte aérea, rendimento e composição química do óleo de hortelã-pimenta. Utilizar adubação orgânica para a obtenção máxima de biomassa seca total as doses de 9,0 kg m-2 de esterco bovino e 8,3 kg m-2 de esterco avícola. O maior rendimento de óleo é obtido com a aplicação de 11,8 kg m-2 de esterco avícola. Diferenças na composição química do óleo essencial foram observadas para três componentes (mentona, pulegona e acetato de mentila) sem mudança significativa no conteúdo de mentol.

Mentha x piperita L. is an aromatic and medicinal species belonging to the family Lamiaceae that is popularly known as peppermint. The aim of this study was to evaluate the effects of organic fertilizer sources on the biomass production, yield and chemical composition of peppermint (Mentha piperita L.) essential oil. The experiment was conducted using a completely randomized design (CRD) with a 2 x 5 factorial scheme, two sources of manure (cattle and poultry), five doses (0, 3, 6, 9 and 12 kg m-2) and four replicates. Different doses of cattle and poultry manure significantly affected plant biomass production and the responses of other variables, including leaf area, leaf weight ratio, leaf area ratio, root:shoot ratio, yield and chemical composition. Organic fertilizer doses of 9.0 kg m-2 cattle manure and 8.3 kg m-2 poultry manure to obtain the maximum total dry biomass. The highest yield of essential oil was obtained by applying 11.8 kg m-2 poultry manure. Differences in the chemical composition of the essential oil were observed for only three components (menthone, pulegone and menthyl acetate) without significant changes in the menthol content.

O objetivo deste trabalho foi avaliar o crescimento vegetativo e o teor, o rendimento e a composição química do óleo essencial de hortelã‑pimenta (Mentha piperita) cultivada sob diferentes malhas, no Município de Lavras, MG. As mudas de hortelã‑pimenta foram cultivadas em cinco ambientes: pleno sol, malha preta, malha aluminizada, malha azul e malha vermelha, todas com 50% de irradiância. Utilizou-se o delineamento experimental inteiramente casualizado, com quatro repetições e cinco plantas por parcela. Foram avaliados os parâmetros: crescimento vegetativo, teor, rendimento e análise química do óleo essencial. Plantas de hortelã‑pimenta cultivadas em pleno sol e sob malhas preta e vermelha produziram maior biomassa seca de folhas e maiores teores e rendimentos do óleo essencial. Entretanto, a pleno sol, o óleo essencial das plantas apresentou maior teor de mentol e, sob as malhas preta e azul, de mentofurano. Portanto, é possível manipular o crescimento das plantas e a produção e a composição química do óleo essencial de hortelã‑pimenta mediante o cultivo sob malhas ou pleno sol.

The objective of this work was to evaluate the growth and the content, yield, and chemical composition of the essential oil of peppermint (Mentha piperita) grown under different nets in Lavras, MG, Brazil. Peppermint plants were grown in five environments: full sun, black net, aluminet net, blue net, and red net, all with 50% of irradiance. The experimental design was a completely randomized block with four replicates and five plants per plot. The evaluated parameters were: vegetative growth, content, yield, and chemical analysis of the essential oil. Peppermint plants grown under full sun and black and red nets produced higher dry leaf biomass and higher essential oil content and yield. However, in full sun, the essential oil of the plants had higher contents of menthol and, under black and blue nets, of menthophurane. Therefore, it is possible to manipulate plant growth and yield and chemical composition of the essential oil of peppermint with cultivation under nets or full sun.

Summary The paper outlines an interpretation of David Hilbert's early axiomatic approach to geometry, i.e., the one developed between 1891 and 1905. It is argued that several aspects of this approach, which could be initially seen as problematic, can be better understood when Hilbert's view is contrasted with one of its most important influences in this period: Heinrich Hertz's "picture theory" [Bildtheorie]. Especially, it will be claimed that an examination of Hilbert's axiomatic conception in the light of the Hertzian view of mechanical theories can be used to relieve the former from certain manifest tensions; more precisely, the tensions that arise when maintaining, at the same time, an abstract or formal axiomatic position and an empiricist view of geometry, which regards it as a kind of natural science.

Resumen El artículo presenta una interpretación del abordaje axiomático temprano a la geometría de David Hilbert, i.e., el desarrollado entre 1891 y 1905. Se sostiene que diversos aspectos de este abordaje, a primera vista problemáticos, se pueden comprender mejor si se contrastan con una de sus influencias más importantes en este periodo: la teoría pictórica [Bildtheorie] de Heinrich Hertz. En particular se argumenta que un análisis de la concepción axiomática de Hilbert a la luz de la teoría de Hertz permite aliviar ciertas tensiones en la concepción hilbertiana; más precisamente, las tensiones que surgen de mantener, al mismo tiempo, una posición axiomática abstracta o formal y una concepción empirista de la geometría, que la considera una ciencia natural.

The paper discusses Hilbert's early axiomatic approach to geometry, particularly his notes for lecture courses between 1891 and 1905 are analyzed. It is argued that, although Hilbert privileged from early on an abstract axiomatic presentation of geometry, he also maintained in this early period more traditional theses, like the claim that geometry is the most perfect of all natural sciences, which deals with the properties or shapes of things in space. Among these, at a first glance, contradictory theses, Hilbert also stresses throughout the lecture courses the importance of "spatial" or "geometrical" intuition for the axiomatization of geometry. The role and notion of spatial intuition in Hilbert's early axiomatic approach are discussed. Finally, this emphasis on the notion of intuition will be used to criticize the standard, formalist view of Hilbert's axiomatic approach to geometry, which will be considered as misleading, or at least inadequate, when his notes for lectures courses are taken into account.

El artículo indaga la concepción axiomática temprana de la geometría de Hilbert. Especialmente, sus notas para cursos sobre geometría entre 1891 y 1905 son analizadas. Se sostendrá que, aunque Hilbert privilegió desde el inicio una presentación axiomática abstracta de la geometría, también mantuvo en este período temprano tesis más tradicionales, como por ejemplo, la afirmación de que la geometría es la más perfecta de las ciencias naturales, que se ocupa de las propiedades o formas de los cuerpos en el espacio. Entre estas tesis, a primera vista contradictorias, Hilbert remarcó además a lo largo de sus cursos la importancia de la intuición 'espacial' o 'geométrica' en la axiomatización de la geometría. La noción y el papel de la 'intuición espacial' en el abordaje axiomático de Hilbert son discutidos. Por último, este énfasis en la noción de intuición será utilizado para criticar la interpretación formalista estándar, que será considerada como errónea, o al menos como inadecuada, a la luz de las fuentes antes mencionadas.

A nutrição mineral da videira constitui-se em importante fator para a qualidade dos vinhos. Devido a isso, avaliou-se o efeito de porta-enxertos no teor de nutrientes em diferentes tecidos da videira 'Cabernet Sauvignon' (Vitis vinifera L.) na Serra Gaúcha. o experimento foi conduzido durante o ciclo vegetativo de 2004/2005, com os porta-enxertos Rupestris du lot, 101-14, 3309, 420A, Kober 5BB, 161-49, So4 e Paulsen 1103, enxertados em 1993 com a cv. 'Cabernet Sauvignon'. o delineamento experimental foi em blocos ao acaso, com oito tratamentos e três repetições, sendo quatro plantas/parcela. Coletaram-se folhas - separando-se os pecíolos dos limbos -, cachos - separando-se as bagas das ráquis - e ramos, os quais foram posteriormente secados em estufa e pesados. Analisaram-se os nutrientes n, P, K, Ca e Mg. os resultados mostram que houve efeito significativo do porta-enxerto nos teores de N, P, K, Ca e Mg no limbo, pecíolo, ráquis e baga da videira 'Cabernet Sauvignon' e que este efeito variou em função do nutriente e do tecido considerado. Entretanto, não houve efeito significativo do porta-enxerto no teor desses nutrientes no ramo da videira. Além disso, a ordem de grandeza do teor dos nutrientes variou em função do tecido avaliado. Assim, os teores de n e de Ca foram maiores no limbo; os de P e K, na ráquis; e o de Mg, no pecíolo.

Grapevine mineral nutrition is an important factor influencing wine quality. For this, the effect of rootstocks on the nutrient content in different tissues of 'Cabernet Sauvignon' grapevines (Vitis vinifera L.) grown in the Serra Gaúcha region was evaluated. The experiment was carried out during the 2004/2005 vegetative cycle with the rootstocks Rupestris du Lot, 101-14, 3309, 420A, Kober 5BB, 161-49, SO4, and Paulsen 1103. The experimental design was in randomized blocks, with eight treatments, three replicates, four plants/plot. leaves - petioles were separated from the limbs -, clusters - berries were separated from the rachis -, and shoots were collected, dried in an oven, and weighted. N, P, K, Ca, and Mg were analyzed. Results show that there was a significant effect of the rootstock on the contents of N, P, K, Ca, and Mg in limb, petiole, rachis and berry of the 'Cabernet Sauvignon' grapevine. This effect varied as a function of the analyzed nutrient and tissue. But there was not a significant effect on the nutrients present in the shoot. Besides this, nutrient content varied according to the kind of tissue analyzed. In this way, contents of N and Ca were higher in limb; contents of P and K, in rachis; and contents of Mg, in petiole.

This paper aims to offer an interpretation of the Transcendental Deduction of the Categories (A) which puts together two of its most distinctive and fundamental traits: the constant reference to the temporal character of the human consciousness and the use of the analytic method of exposition. We will defend the thesis that the connection between both traits is essential, i. e., it will be argued that it is precisely the usage of the analytic method what confers to the pure consciousness of time a significant role in the structure of the argument. With this thesis an alternative reading of the A-Deduction is pursued, one which moves away from the predominant one which claims that Kant's persistent allusion in it to the pure time representation - and to the synthesis which make it possible - is just a direct consequence of its psychological character.

El objetivo del artículo es ofrecer una interpretación de la Deducción Transcendental de las Categorías (A) que ponga en relación dos de sus aspectos más distintivos y fundamentales: la referencia permanente al carácter temporal de la conciencia humana, y la utilización del método analítico de exposición. Se defenderá la tesis de que la conexión entre ambos aspectos es esencial, en tanto que es precisamente la adopción del método analítico lo que determina que se le confiera a la conciencia pura del tiempo un rol fundamental en la estructura del argumento. Con esta tesis se intenta ofrecer una lectura alternativa de la Deducción A, que se diferencie de la habitual según la cual la apelación constante de Kant a la representación pura del tiempo - y a las síntesis que lo hacen posible - es una consecuencia directa del carácter psicologista que la distingue.

The thyroid carcinoma (TC) is not very frequent among all cancers. Its course is slow and is high potentially curable. Our aim was to analyse the characteristics in patients with TC. A retrospective analysis on 171 patients, with an average age of 41.1 (±14,6), who asked for TC to our service between the years 2000-04, was performed. From case histories it was evaluated: anamnesis, diagnostic image, histopathology and evolution. Tumours were grouped for size and TNM (tumour-nodule-metastasis) in stages (S). A stimulated serum thyroglobulin level > 2 ng/ml and positive image with 131I or another nuclear marker were considered as positive for residual TC. In the totality of the analyzed patients 88% were female, 62% below 45 years old, and in 77% the thyroid function was normal. The fine needle aspiration (FNA) was diagnostic in 78%. Papillary thyroid carcinoma (PTC) in 96%. The 63% was SI; 14% SII; 19% SIII and 4% SIV. During follow-up, we observed that 90% of patients with Tg between 2 and 10 had evidence of residual TC, and 100% with Tg > 10 ng/ml, whereas 18% of those whose stimulated Tg < 2 presented positive image. There was not found significative correlation with pathologic antecedents or relevant image signs. In conclusion: TCP was the most frequent carcinoma in women, in patients younger than 45 years and in those who have euthyroid function. A stimulated serum thyroglobulin level was a good indicator for residual TC, but failed to select those patients who were disease free.

Entre todos los tumores, el carcinoma tiroideo (CT) es poco frecuente, se caracteriza por su lenta evolución y elevado porcentaje de curación. Nuestro objetivo es estudiar las características de los pacientes con CT. Analizamos retrospectivamente a 171 pacientes, edad media al diagnóstico 41.1( ± 14.6 años), que consultaron entre los años 2000-04 por CT. Se evaluaron datos de anamnesis, métodos de diagnóstico, anatomía patológica y evolución. Agrupamos a los tumores por el tamaño y según TNM (tumor-adenopatía-metástasis) en estadios (E). La presencia de tiroglobulina estimulada (Tg) > 2 ng/ml e imagen positiva (con 131I u otro radiotrazador) fueron consideradas como positivas para CT residual. De la población total el 88% fue sexo femenino, el 62% menores de 45 años, y el 77.1% tuvo función tiroidea normal. La punción con aguja fina (PAAF) fue diagnóstica en 78%. El 96% fue carcinoma papilar (CTP), 63% presentaban E I; 14% E II; 19% E III y 4% E IV. Se detectó CT residual en el 90% de los pacientes con Tg entre 2 y 10, y en el 100% con Tg > 10 ng/ml, mientras que con Tg < 2 el 18% mostró imagen positiva. No encontramos correlación significativa con antecedentes patológicos ni con ningún signo relevante en imágenes. En conclusión, en nuestra población el CTP fue predominante. Más frecuente en mujeres, en menores de 45 años y en eutiroideos. El nivel de Tg estimulada es un buen indicador de CT residual, pero no es una prueba suficiente para seleccionar pacientes libres de enfermedad.