Nectaries and reproductive biology of Croton sarcopetalus (Euphorbiaceae)

Flower morphology, nectary structure, nectar chemical composition, breeding system, floral visitors and pollination were analysed in Croton sarcopetalus, a diclinous-monoecious shrub from Argentina. Male flowers have five receptacular nectaries, with no special vascular bundles, that consist of a uniserial epidermis with stomata subtended by a secretory parenchyma. Female flowers bear two different types of nectaries: inner (IN) and outer (ON) floral nectaries. IN, five in all, are structurally similar to the nectaries of male flowers. The five ON are vascularized, stalked, and composed of secretory, column-shaped epidermal cells without stomata subtended by secretory and ground parenchyma. In addition, ON act as post-floral nectaries secreting nectar during fruit ripening. Extrafloral nectaries (EFN) are located on petioles, stipules and leaf margins. Petiolar EFN are patelliform, stalked and anatomically similar to the ON of the female flower. Nectar sampled from all nectary types is hexose dominant, except for the ON of the female flower at the post-floral stage that is sucrose dominant. The species is self-compatible, but geitonogamous fertilization is rarely possible because male and female flowers are not usually open at the same time in the same individual, i.e. there is temporal dioecism. Flowers are visited by 22 insect species, wasps being the most important group of pollinators. No significant differences were found in fruit and seed set between natural and hand pollinated flowers. This pattern indicates that fruit production in this species is not pollen/pollinator limited and is mediated by a wide array of pollinators. (C) 2001 the Linnean Society of London.

Zoogeography of Chiropotes albinasus (Platyrrhini, Atelidae) in southwestern Amazonia

White-nosed bearded sakis (Chiropotes albinasus) are endemic to the Madeira-Xingu interfluvium in southern Amazonia, though recent fieldwork has produced conflicting data on the southwestern limits of the species's geographic range. We reevaluated the distribution of bearded sakis on the basis of surveys from 34 sites throughout the Brazilian state of Rondonia. Chiropotes albinasus occurred at seven sites in the eastern part of the state, including two west of the Jiparana-Pimenta Bueno river system in the extreme south, but there is no record of their presence further north and west in the Jiparana-Guapore interfluvium and they were absent from the Jiparana-Mamore interfluvium. The data suggest that ecological, rather than geographic barriers restrict the distribution of Chiropotes albinasus in southern Rondonia, but are contradictory with regard to the possible determining factors. Chiropotes albinasus appears able to thrive in transitional, savanna-like ecosystems in southern Rondonia, but is unexpectedly absent from adjacent areas of terra firme forest. Syntopy with the only other pitheciine found in the state (Pithecia irrorata) appears to have a negative effect on the abundance of Chiropotes albinasus which implies that interspecific competition may reinforce a complex of limiting factors, such as the availability of key plant species. Despite showing that Chiropotes albinasus is widespread in southern Rondonia, we also confirm its absence from the western two thirds of the state, a significant reduction in the known range of the species.

Diet of buffy tufted-eared marmosets (Callithrix aurita) in a forest fragment in southeastern Brazil

The feeding ecology of the Atlantic forest marmosets (Callithrix spp.) in southeastern Brazil is poorly known, and few studies have focused on buffy tufted-eared marmosets, Callithrix aurita. We determined the food items and investigated the seasonal variation in the diet of a group of four Callithrix aurita in a 17-ha semideciduous forest fragment in southern Minas Gerais State, Brazil. We recorded daily feeding activities between October 1994 and September 1995 using scan sampling at 5-min intervals. The marmosets devoted feeding rime to gums (50.5%), fruits (11%), and animal prey (38.5%) in a fetal of 499 records. Plant resources comprised 27 species from 16 families. They used Acacia paniculata (Mimosoideae, Leguminosae), the main gum source (82%), year-round Maclura tinctoria (Moraceae) was the fruit species that they consumed most (22%). The marmosets preyed on caterpillars (33%), katydids (5%), and homopterans (4%). Feeding on fruits varied seasonally and was inversely related to gum feeding. Consumption of animal prey remained constant over the year. The wide and year-round dependence on gum suggests that Acacia may play a critical role in marmoset persistence in forest fragments.

Tree-level violation of the equivalence principle

Massive particles of spin 0 and 1 violate the equivalence principle (EP) at the tree level. on the other hand, if these particles are massless, they agree with the EP, which leads us to conjecture that from a semiclassical viewpoint massless particles, no matter what their spin, obey the EP. General relativity predicts a deflection angle of 2.63' for a nonrelativistic spinless massive boson passing close to the Sun, while for a massive vectorial boson of spin 1 the corresponding deflection is 2.62'.

Gravitation and the local symmetry group of space-time

According to general relativity, the interaction of a matter field with gravitation requires the simultaneous introduction of a tetrad field, which is a field related to translations, and a spin connection, which is a field assuming values in the Lie algebra of the Lorentz group. These two fields, however, are not independent. By analyzing the constraint between them, it is concluded that the relevant local symmetry group behind general relativity is provided by the Lorentz group. Furthermore, it is shown that the minimal coupling prescription obtained from the Lorentz covariant derivative coincides exactly with the usual coupling prescription of general relativity. Instead of the tetrad, therefore, the spin connection is to be considered as the fundamental field representing gravitation.

Contribution of forest species to the floristic composition of a forested savanna in southeastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desempenho cognitivo-linguístico de escolares com distúrbio de aprendizagem

O estudo tem como objetivo caracterizar e comparar o desempenho cognitivo-linguístico de escolares com distúrbio de aprendizagem com escolares com bom desempenho acadêmico. Participaram 40 escolares de 8 a 12 anos de idade, de 2ª a 4ª séries do Ensino Fundamental de escolas municipais da cidade de Marília - SP, divididos em GI (escolares com bom desempenho acadêmico) e GII (escolares com distúrbio de aprendizagem). Como procedimento foi utilizado o Teste de Desempenho Cognitivo-Linguístico, versões coletiva e individual. Os resultados evidenciaram desempenho superior do GI em relação ao GII nas habilidades de leitura, escrita, velocidade de processamento, processamento auditivo e visual. Concluiu-se que o desempenho inferior do GII nas habilidades indica uma limitação no desempenho linguístico desses escolares se comparados com os do GI, exceto na habilidade de consciência fonológica, em que, os grupos apresentaram dificuldades semelhantes, sugerindo que essa dificuldade não seja específica de escolares com distúrbio de aprendizagem.

The Chilean earthquake of 27 February 2010 an overview

Includes bibliography

Abreviar (distâncias) na internet, conectar-se ao mundo (na linguagem)

This article aims to investigate the abbreviations used on chats by web-surfers between 15 and 20 years old. The material consists of two virtual conversations of about 60 minutes each. We believe that this linguistic process occurs due to the physical distance that separates affectively the web-surfers by modifying already said utterances in written practices characterized by short time of interaction. This abbreviation process, known as a characteristic of the so called internetês, is not considered as a simple attempt to cut the words, but as a resource that presents linguistics' regularity. Therefore, the theory of phonological syllable is used as a tool in order to verify the process that forms possible abbreviations used on chats. It is believed that, based on the study of the syllable structure, the choice of the graphemes abbreviation may be assessed based on the writing heterogeneity, since the writer might not only use oral/spoken practices but also literate/written ones so as to produce utterances that emerge in the contemporaneity.

In memory of Pedro Vuskovic

For those of us who shared many years of friendship and professional collaboration with Pedro Vuskovic, the news of his recent death in Mexico has been the cause of great sorrow, not only because of the circumstances of his death, following a cruel disease that gradually sapped his physical -but not intellectual- strength, but also because it signifies the loss of a great Latin American, of a teacher who helped shape so many generations of young people in our region, and of a companion during so many days of intellectual strivings and political struggle. Pedro joined the Commission in 1950, shortly after its birth as an institution. For nearly 20 years he served it brilliantly in a professional capacity, with his career in ECLAC culminating in the position of Director of the Development Division. He played a crucial role in structuring and disseminating the thinking of ECLAC during a time when the very air teemed with the ideas and concerns of a pleiad of gifted economists and social scientists. These were the post-war years, the 1950s and 1960s, when we all had to "construct" Latin America. Pedro Vuskovic laid many of the bricks in that collective theoretical and political edifice which has been of such importance to the countries of the region. Concurrently, he served as a professor in ECLAC and ILPES training programmes while at the same time teaching classes at the schools of economics and sociology at the University of Chile and the School of Economics at the University of Concepción. When he left ECLAC, Pedro plunged wholeheartedly into the academic world, serving as the Director of the Institute of Economics of the University of Chile, and then went on to claim a position at the forefront of Chilean politics. In November 1970 he was named Minister of Economic Affairs by President Salvador Allende and in June 1972, took over the cabinet-level position of Executive Vice President of the Production Development Corporation (CORFO);, where he served until September 1973. When political events carried him into exile in Mexico, which generously welcomed him as it did so many other Latin Americans who faced similar problems, Pedro carried on his valuable academic work, first at the Economic Research and Teaching Centre (CIDE);, where he directed the Institute of Economic Studies of Latin America, and later at the Centre for Interdisciplinary Research in the Humanities at the National University of Mexico (UNAM);, where he was named to the position of Coordinator for a programme on poverty and development options in various countries of Latin America. Although he will be remembered for his important political role, Pedro's work as a scholar and as an economist deserve special mention. He was a brilliant speaker, at the same time both methodical and incisive, who mastered his subjects with great wisdom and intellectual breadth, and he derived a special joy from being with young people, from providing them with intellectual stimulation and receiving it from them in turn. The many generations of Latin American students who were fortunate enough to have him as a teacher can attest to this. Pedro Vuskovic brought to his work as a researcher and teacher a deep sense of political and social responsibility which moved him to espouse the cause of Latin America 's poor and dispossessed, whose position he had come to understand very early on in his life through the many studies he carried out in this area while at ECLAC. He was tenacious in upholding his ideas and principles, he lived in accordance with them, and he championed them in all the forums open to him, in both the political and academic worlds, to the end of his days. His friends and colleagues also remember his geniality, his sense of humour and great personal warmth -traits which were coupled with an unshakable loyalty to his principles and values. Our farewell is deeply felt; Pedro Vuskovic has left us a legacy of memories and lessons that we will always hold close to our hearts. On behalf of his friends and colleagues, Jacobo Schatan, former Director of the Joint ECLAC/FAO, Agriculture Division

The dynamic of employment in Chilean industry

Includes bibliography

Productive structure and the functional distribution of income: an application of the input-output model

Includes bibliography

Preliminary assessment of the quantitative relationships between testicular tissue composition and ultrasonographic image attributes in the ram

This study examined the relationships between gross chemical composition and ultrasonographic characteristics of the ram testes. Ten testes from sexually mature Karakul rams were scanned ex situ with an 8-MHz linear-array transducer, in a transverse and longitudinal plane. All ultrasonograms were saved as digital images and subjected to computerized analyses. Crude protein content was determined by the Kjeldahl method, moisture was determined with an oven-drying method, and fat was measured by the Soxhlet extraction of dried samples. Mean pixel values (r = -0.64, P = 0.04), pixel heterogeneity (standard deviation of pixel values; r = -0.64, P = 0.04) and maximum pixel intensity (r = -0.76, P = 0.01) were all negatively correlated with parenchymal protein content. Pixel heterogeneity correlated directly with extractable lipids (r = 0.66, P = 0.02). The quantitative correlations between echotextural and biochemical parameters found in the present experiment confirm the utility of ultrasonographic imaging combined with computer-assisted image analysis for determining changes in testicular histophysiology. © 2013 Elsevier Ltd. All rights reserved.

Ausência de vírgulas em bate-papos virtuais produzidos por crianças: um enfoque prosódico-discurso

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)