The colors of paintings and viewers' preferences.

One hypothesis to explain the aesthetics of paintings is that it depends on the extent to which they mimic natural image statistics. In fact, paintings and natural scenes share several statistical image regularities but the colors of paintings seem generally more biased towards red than natural scenes. Is the particular option for colors in each painting, even if less naturalistic, critical for perceived beauty? Here we show that it is. In the experiments, 50 naïve observers, unfamiliar with the 10 paintings tested, could rotate the color gamut of the paintings and select the one producing the best subjective impression. The distributions of angles obtained are described by normal distributions with maxima deviating, on average, only 7 degrees from the original gamut orientation and full width at half maximum just above the threshold to perceive a chromatic change in the paintings. Crucially, for data pooled across observers and abstract paintings the maximum of the distribution was at zero degrees, i.e., the same as the original. This demonstrates that artists know what chromatic compositions match viewers' preferences and that the option for less naturalistic colors does not constrain the aesthetic value of paintings.

Statistics of colors in paintings and natural scenes.

Painters reproduce some spatial statistical regularities of natural scenes. To what extent they replicate their color statistics is an open question. We investigated this question by analyzing the colors of 50 natural scenes of rural and urban environments and 44 paintings with abstract and figurative compositions. The analysis was carried out using hyperspectral imaging data from both sets and focused on the gamut and distribution of colors in the CIELAB space. The results showed that paintings, like natural scenes, have gamuts with elongated shapes in the yellow-blue direction but more tilted to the red direction. It was also found that the fraction of discernible colors, expressed as a function of the number of occurrences in the scene or painting, is well described by power laws. These have similar distribution of slopes in a log-log scale for paintings and natural scenes. These features are observed in both abstract and figurative compositions. These results suggest that the underlying chromatic structure of artistic compositions generally follows the main statistical features of the natural environment.

Ochres and earths: matrix and chromophores characterization of 19th and 20th century artist materials.

The present paper describes the main results obtained from the characterization of a wide range of natural and synthetic ochre samples used in Portugal from the 19th to the 20th century, including powder and oil painting samples. The powder ochre samples came from several commercial distributors and from the collection of Joaquim Rodrigo (1912-1997), a leading Portuguese artist, particularly active during the sixties and seventies. The micro-samples of oil painting tubes came from the Museu Nacional de Arte Contemporânea-Museu do Chiado (National Museum of Contemporary Art-Chiado Museum) in Lisbon and were used by Columbano Bordalo Pinheiro (1857-1929), one of the most prominent naturalist Portuguese painters. These tubes were produced by the main 19th century colourmen: Winsor & Newton, Morin et Janet, Maison Merlin, and Lefranc. The samples have been studied using µ-Fourier Transform Infrared Spectroscopy (µ-FTIR), Raman microscopy, µ-Energy Dispersive X-ray fluorescence (µ-EDXRF), and X-ray diffraction (XRD). The analyzed ochres were found to be a mixture of several components: iron oxides and hydroxides in matrixes with kaolinite, gypsum and chalk. The results obtained allowed to identify and characterize the ochres according to their matrix and chromophores. The main chromophores where identified by Raman microscopy as being hematite, goethite and magnetite. The infrared analysis of the ochre samples allowed to divide them into groups, according to the composition of the matrix. It was possible to separate ochres containing kaolinite matrix and/or sulfate matrix from ochres where only iron oxides and/or hydroxides were detected. µ-EDXRF and Raman were the best techniques to identify umber, since the presence of elements such as manganese is characteristic of these pigments. µ-EDXRF also revealed the presence of significant amounts of arsenic in all Sienna tube paints.

Library of UV-Vis-NIR reflectance spectra of modern organic dyes from historic pattern-card coloured papers.

An accurate characterisation of the organic dyes used in artworks, especially those made of paper, is an important factor in designing safe conservation treatments. In the case of synthetic organic dyes used in modern works of art, for example, one frequently encountered difficulty is that some of these dyes are not still commercially available. Recognizing this problem, the authors of this paper present the results of an analysis of UV-Vis-NIR fibre optic reflectance spectra of 82 samples of dyed paper prepared with 41 dyes. The samples come from a historic book, The Dyeing of Paper in the Pulp, which was published by Interessen-Gemeinschaft (I.G.) Farbenindustrie in 1925. The dyes used in the paper pulp belong to the azo compounds, acridine, anthraquinone, azine, diphenylmethane, indigoid, methine, nitro, quinoline, thiazine, triphenylmethane, sulphur and xanthene classes.

Antifungal activity of coumarins.

The antifungal activity of 40 coumarins was tested against the fungal strains: Candida albicans (ATCC 14053), Aspergillus fumigatus (ATCC 16913) and Fusarium solani (ATCC 36031), using the broth microdilution method. Osthenol showed the most effective antifungal activity among all the compounds tested, with a MIC value of 125 microg/ml for Fusarium solani and 250 micro/ml for Candida albicans and Aspergillus fumigatus. The antifungal potential of this prenylated coumarin can be related to the presence of an alkyl group at C-8 position.

Prevalência de casos de Mycoplasma hominis e Ureaplasma urealyticum nas secreções endocervicais e urinas de primeiro jato em Laboratório de Análises Clínicas de Brusque - SC / Prevalence of cases Mycoplasma hominis and Ureaplasma urealyticum in endocervical secretions and first jet of urine in a laboratory of clinic analysis in Brusque - SC

Mycoplasma hominis e Ureaplasma urealyticum são os menores e mais simples procariontes que conseguem ter vida livre na natureza; desprovidos de parede celular, possuem apenas uma membrana lipoprotéica. Podem ser isolados do trato geniturinário de homens e mulheres assintomáticos como comensais mas, também, podem ser considerados agentes de uretrites, prostatites, epididimites, vaginoses, doença inflamatória pélvica, abortos, partos prematuros, corioamnionites, salpingites, febre puerperal, infertilidade, pielonefrites e infecções no recém-nascido. O presente trabalho visou estabelecer a prevalência de M. hominis e U. urealyticum em secreções endocervicais e urinas de primeiro jato no Laboratório Hoffmann de Análises Clínicas de Brusque, Santa Catarina, no período de agosto a dezembro de 2003. Foram analisadas 62 secreções endocervicais e 32 urinas de primeiro jato; utilizando o Kit para Micoplasma (Newprov), que permite identificação, quantificação e crescimento de colônias. Desenvolveram crescimento 25,8% das secreções endocervicais e 28,1% das urinas de primeiro jato, foi verificada presença de abundantes leucócitos em um número significativo de amostras e encontrou-se, nas secreções endocervicais, associação dos micoplasmas com outras patologias. Os resultados obtidos revelaram que o M. hominis e o U. urealyticum são patógenos importantes e devem ser pesquisados, identificados e quantificados como exames de rotina nos laboratórios de análises clínicas.

Mycoplasma hominis and Ureaplasma urealyticum are the smallers and the simplest procariont that achieves having a life free in the nature, without cellular wall, owning only a lipoprotein membrane. They can be alone in men and women geniturinariun treatment bringing no symptoms as comensals, but they can be considered uretrits agents, prostatits, epididimits, vaginoses, pelvic inflammation illness, abortion, premature chilbirth, corioamnionits, salpingits, puerperal fever, no possibility of having children, pielonefrits and infections in babies that have just borned. This present article tried to estabilish the prevalence of Mycoplasma hominis and Ureaplasma urealyticum in endocervical secretions and first jet of urine in the Hoffmann laboratory of clinic analysis located in Brusque, Santa Catarina, during the period from August to December of 2003. We analyzed 62 endocervical secretions and 32 first jet of urine, using the Kit for “Micoplasma” (Newprov), that permited the identification, qualification and the colonies growth. 25,8% of the endocervical secretions and 28,1% of the first jet of urine desenvolved a growth, which was noticed the appearance of abundats white cells in a meaningful number of samples and was found, in the endocervical secretions, the association of micoplasm with others pathologies. The results gotten, exposed that M. hominis and U. Urealyticum are impostants pathogen and should be searched, identified and qualidified as daly exams in laboratorys of clinic analysis.